--- layout: docs page_title: Upgrade Guides description: |- Specific versions of Nomad may have additional information about the upgrade process beyond the standard flow. --- # Upgrade Guides The [upgrading page](/docs/upgrade) covers the details of doing a standard upgrade. However, specific versions of Nomad may have more details provided for their upgrades as a result of new features or changed behavior. This page is used to document those details separately from the standard upgrade flow. ## Nomad 1.5.0 #### Artifact Download Sandboxing Nomad 1.5.0 changes the way [artifacts] are downloaded when specifying an `artifact` in a task configuration. Previously the Nomad Client would download artifacts in-process. External commands used to facilitate the download (e.g. `git`, `hg`) would be run as `root`, and the resulting payload would be owned as `root` in the allocation's task directory. In an effort to improve the resilience and security model of the Nomad Client, in 1.5.0 artifact downloads occur in a sub-process. Where possible, that sub-process is run as the `nobody` user, and on modern Linux systems will be isolated from the filesystem via the kernel's [landlock] capabilitiy. Operators are encouraged to ensure jobs making use of artifacts continue to work as expected. In particular, git-ssh users will need to make sure the system-wide `/etc/ssh/ssh_known_hosts` file is populated with any necessary remote hosts. Previously, Nomad's documentation suggested configuring `/root/.ssh/known_hosts` which would apply only to the `root` user. The artifact downloader no longer inherits all environment variables available to the Nomad Client. The downloader sub-process environment is set as follows on Linux / macOS: ``` PATH=/usr/local/bin:/usr/bin:/bin TMPDIR=/tmp ``` and as follows on Windows: ``` TMP=\tmp TEMP=\tmp PATH= HOMEPATH= HOMEDRIVE= USERPROFILE= ``` Configuration of the artifact downloader should happen through the [`options`][artifact_params] and [`headers`][artifact_params] fields of the `artifact` block. For backwards compatibility, the sandbox can be configured to inherit specified environment variables from the Nomad client by setting [`set_environment_variables`][artifact_env]. The use of filesystem isolation can be disabled in Client configuration by setting [`disable_filesystem_isolation`][artifact_fs_isolation]. #### Server `rejoin_after_leave` (default: `false`) now enforced All Nomad versions prior to v1.5.0 have incorrectly ignored the Server [`rejoin_after_leave`] configuration option. This bug has been fixed in Nomad version v1.5.0. Previous to v1.5.0 the behavior of Nomad `rejoin_after_leave` was always `true`, regardless of Nomad server configuration, while the documentation incorrectly indicated a default of `false`. Cluster operators should be aware that explicit `leave` events (such as `nomad server force-leave`) will now result in behavior which matches this configuration, and should review whether they were inadvertently relying on the buggy behavior. #### Changes to eval broker metrics The metric `nomad.nomad.broker.total_blocked` has been changed to `nomad.nomad.broker.total_pending`. This state refers to internal state of the leader's broker, and this is easily confused with the unrelated evaluation status `"blocked"` in the Nomad API. ## Nomad 1.4.0 #### Possible Panic During Upgrades Nomad 1.4.0 initializes a keyring on the leader if one has not been previously created, which writes a new raft entry. Users have reported that the keyring initialization can cause a panic on older servers during upgrades. Following the documented [upgrade process][] closely will reduce the risk of this panic. But if a server with version 1.4.0 or higher becomes leader while servers with versions before 1.4.0 are still in the cluster, the older servers will panic. The most likely scenario for this is if the leader is still on a version before 1.4.0 and is netsplit from the rest of the cluster or the server is restarted without upgrading, and one of the 1.4.0 servers becomes the leader. You can recover from the panic by immediately upgrading the old servers. #### Raft Protocol Version 2 Unsupported Raft protocol version 2 was deprecated in Nomad v1.3.0, and is being removed in Nomad v1.4.0. In Nomad 1.3.0, the default raft protocol version was updated to version 3, and in Nomad 1.4.0 Nomad requires the use of raft protocol version 3. If [`raft_protocol`] version is explicitly set, it must now be set to `3`. For more information see the [Upgrading to Raft Protocol 3] guide. #### Audit logs filtering logic changed Audit Log filtering in previous versions of Nomad handled `stages` and `operations` filters as `OR` filters. If _either_ condition was met, the logs would be filtered. As of 1.4.0, `stages` and `operations` are treated as `AND filters`. Logs will only be filtered if all filter conditions match. #### Prevent Overlapping New Allocations with Stopping Allocations Prior to Nomad 1.4.0 the scheduler would consider the resources used by allocations that are in the process of stopping to be free for new allocations to use. This could cause newer allocations to crash when they try to use TCP ports or memory used by an allocation in the process of stopping. The new and stopping [allocations would "overlap" improperly.][alloc_overlap] [Nomad 1.4.0 fixes this behavior][gh_10446] so that an allocation's resources are only considered free for reuse once the client node the allocation was running on reports it has stopped. Technically speaking: only once the `Allocation.ClientStatus` has reached a terminal state (`complete`, `failed`, or `lost`). Despite this being a bug fix, it is considered a significant enough change in behavior to reserve for a major Nomad release and *not* be backported. Please report any negative side effects encountered as [new issues.][gh_issue] #### `nomad eval status -json` Without Evaluation ID Removed Using `nomad eval status -json` without providing an evaluation ID was deprecated in Nomad 1.2.4 with the intent to remove in Nomad 1.4.0. This option has been removed. You can use `nomad eval list` to get a list of evaluations and can use `nomad eval list -json` to get that list in JSON format. The `nomad eval status ` command will format a specific evaluation in JSON format if the `-json` flag is provided. #### Removing Vault/Consul from Clients Nomad clients no longer have their Consul and Vault fingerprints cleared when connectivity is lost with Consul and Vault. To intentionally remove Consul and Vault from a client node, you will need to restart the Nomad client agent. #### Numeric Operand Comparisons in Constraints Prior to Nomad 1.4.0 the `<, <=, >, >=` operators in a constraint would always compare the operands lexically. This behavior has been changed so that the comparison is done numerically if both operands are integers or floats. ## Nomad 1.3.3 Environments that don't support the use of [`uid`][template_uid] and [`gid`][template_gid] in `template` blocks, such as Windows clients, may experience task failures with the following message after upgrading to Nomad 1.3.3: ``` Template failed: error rendering "(dynamic)" => "...": failed looking up user: managing file ownership is not supported on Windows ``` It is recommended to avoid this version of Nomad in such environments. ## Nomad 1.3.2, 1.2.9, 1.1.15 #### Client `max_kill_timeout` now enforced Nomad versions since v0.9 have incorrectly ignored the Client [`max_kill_timeout`][max_kill_timeout] configuration option. This bug has been fixed in Nomad versions v.1.3.2, v1.2.9, and v1.1.15. Job submitters should be aware that a Task's [`kill_timeout`][kill_timeout] will be reduced to the Client's `max_kill_timeout` if the value exceeds the maximum. ## Nomad 1.3.1, 1.2.8, 1.1.14 #### Default `artifact` limits Nomad 1.3.1, 1.2.8, and 1.1.14 introduced mechanisms to limit the size of `artifact` downloads and how long these operations can take. The limits are defined in the new [`artifact`client configuration][client_artifact] and have predefined default values. While the defaults set are fairly large, it is recommended to double-check them prior to upgrading your Nomad clients to make sure they fit your needs. ## Nomad 1.3.0 #### Raft Protocol Version 2 Deprecation Raft protocol version 2 will be removed from Nomad in the next major release of Nomad, 1.4.0. In Nomad 1.3.0, the default raft protocol version has been updated to 3. If the [`raft_protocol`] version is not explicitly set, upgrading a server will automatically upgrade that server's raft protocol. See the [Upgrading to Raft Protocol 3] guide. #### Client State Store The client state store will be automatically migrated to a new schema version when upgrading a client. Downgrading to a previous version of the client after upgrading it to Nomad 1.3 is not supported. To downgrade safely, users should drain all tasks from the Nomad client and erase its data directory. #### CSI Plugins The client filesystem layout for CSI plugins has been updated to correctly handle the lifecycle of multiple allocations serving the same plugin. Running plugin tasks will not be updated after upgrading the client, but it is recommended to redeploy CSI plugin jobs after upgrading the cluster. The directory for plugin control sockets will be mounted from a new per-allocation directory in the client data dir. This will still be bind-mounted to `csi_plugin.mount_config` as in versions of Nomad prior to 1.3.0. The volume staging directory for new CSI plugin tasks will now be mounted to the task's `NOMAD_TASK_DIR` instead of the `csi_plugin.mount_config`. #### Raft leadership transfer on error Starting with Nomad 1.3.0, when a Nomad server is elected the Raft leader but fails to complete the process to start acting as the Nomad leader it will attempt to gracefully transfer its Raft leadership status to another eligible server in the cluster. This operation is only supported when using Raft Protocol Version 3. #### Server Raft Database The server raft database in `raft.db` will be automatically migrated to a new underlying implementation provided by `go.etcd.io/bbolt`. Downgrading to a previous version of the server after upgrading it to Nomad 1.3 is not supported. Like with any Nomad upgrade it is recommended to take a snapshot of your database prior to upgrading in case a downgrade becomes necessary. The new database implementation enables a new server configuration option for controlling the underlying freelist-sync behavior. Clusters experiencing extreme disk IO on servers may want to consider disabling freelist-sync to reduce load. The tradeoff is longer server startup times, as the database must be completely scanned to re-build the freelist from scratch. ```hcl server { raft_boltdb { no_freelist_sync = true } } ``` #### Changes to the `nomad server members` command The standard output of the `nomad server members` command replaces the previous `Protocol` column that indicated the Serf protocol version with a new column named `Raft Version` which outputs the Raft protocol version defined in each server. The `-detailed` flag is now called `-verbose` and outputs the standard values in addition to extra information. The previous name is still supported but may be removed in future releases. The previous `Protocol` value can be viewed using the `-verbose` flag. #### Changes to `client.template.function_denylist` configuration consul-template v0.28 added a new function [`writeToFile`](https://github.com/hashicorp/consul-template/blob/v0.28.0/docs/templating-language.md#writeToFile) which can write to arbitrary files on the host. Nomad 1.3.0 disables this function by default in its [`function_denylist`](/docs/configuration/client#function_denylist). However *if you have overridden the default `template.function_denylist` in your client configuration, you must add `writeToFile` to your denylist.* Failing to do so allows templates to write to arbitrary paths on the host. #### Changes to Envoy metrics labels When using Envoy as a sidecar proxy for Connect enabled services, Nomad will now automatically inject the unique allocation ID into Envoy's stats tags configuration. Users who wish to set the tag values themselves may do so using the [`proxy.config`](/docs/job-specification/proxy#config) block. ```hcl connect { sidecar_service { proxy { config { envoy_stats_tags = ["nomad.alloc_id="] } } } } ``` #### Changes to Consul Connect Service Identity Tokens Starting with Nomad 1.3.0, Consul Service Identity Tokens created automatically by Nomad on behalf of Connect services will now be created as [`Local`] tokens. These tokens will no longer be replicated globally. To facilitate cross-Consul datacenter requests of Connect services registered by Nomad, Consul agents will need to be configured with [default anonymous][anon_token] ACL tokens with ACL policies of sufficient permissions to read service and node metadata pertaining to those requests. This mechanism is described in Consul [#7414][consul_acl]. A typical Consul agent anonymous token may contain an ACL policy such as: ```hcl service_prefix "" { policy = "read" } node_prefix "" { policy = "read" } ``` The minimum version of Consul supported by Nomad's Connect integration is now Consul v1.8.0. #### Changes to task groups that utilise Consul services and checks Starting with Nomad 1.3.0, services and checks that utilise Consul will have an automatic constraint placed upon the task group. This ensures they are placed on a client with a Consul agent running that meets a minimum version requirement. The minimum version of Consul supported by Nomad's service and check stanzas is now Consul v1.7.0. #### Linux Control Groups Version 2 Starting with Nomad 1.3.0, Linux systems configured to use [cgroups v2][cgroups2] are now supported. A Nomad client will only activate its v2 control groups manager if the system is configured with the cgroups2 controller mounted at `/sys/fs/cgroup`. * Systems that do not support cgroups v2 are not affected. * Systems configured in hybrid mode typically mount the cgroups2 controller at `/sys/fs/cgroup/unified`, so Nomad will continue to use cgroups v1 for these hosts. * Systems configured with only cgroups v2 now correctly support setting cpu [cores]. Nomad will preserve the existing cgroup for tasks when a client is upgraded, so there will be no disruption to tasks. A new client attribute `unique.cgroup.version` indicates which version of control groups Nomad is using. When cgroups v2 are in use, Nomad uses `nomad.slice` as the [default parent][cgroup_parent] for cgroups created on behalf of tasks. The cgroup created for a task is named in the form `..scope`. These cgroups are created by Nomad before a task starts. External task drivers that support containerization should be updated to make use of the new cgroup locations. The new cgroup file system layout will look like the following: ```shell-session ➜ tree -d /sys/fs/cgroup/nomad.slice /sys/fs/cgroup/nomad.slice ├── 8b8da4cf-8ebf-b578-0bcf-77190749abf3.redis.scope └── a8c8e495-83c8-311b-4657-e6e3127e98bc.example.scope ``` #### Support for pre-0.9 Tasks Removed Running tasks that were created on clusters from Nomad version 0.9 or earlier will fail to restore after upgrading a cluster to Nomad 1.3.0. To safely upgrade without unplanned interruptions, force these tasks to be rescheduled by `nomad alloc stop` before upgrading. Note this only applies to tasks that have been running continuously from before 0.9 without rescheduling. Jobs that were created before 0.9 but have had tasks replaced over time after 0.9 will operate normally during the upgrade. ## Nomad 1.2.6, 1.1.12, and 1.0.18 #### ACL requirement for the job parse endpoint Nomad 1.2.6, 1.1.12, and 1.0.18 require ACL authentication for the [job parse][api_jobs_parse] API endpoint. The `parse-job` capability has been created to allow access to this endpoint. The `submit-job`, `read`, and `write` policies include this capability. The capability must be enabled for the namespace used in the API request. ## Nomad 1.2.4 #### `nomad eval status -json` deprecated Nomad 1.2.4 includes a new `nomad eval list` command that has the option to display the results in JSON format with the `-json` flag. This replaces the existing `nomad eval status -json` option. In Nomad 1.4.0, `nomad eval status -json` will be changed to display only the selected evaluation in JSON format. ## Nomad 1.2.2 ### Panic on node class filtering for system and sysbatch jobs fixed Nomad 1.2.2 fixes a [server crashing bug][gh-11563] present in the scheduler node class filtering since 1.2.0. Users should upgrade to Nomad 1.2.2 to avoid this problem. ## Nomad 1.2.0 #### Nvidia device plugin The Nvidia device is now an external plugin and must be installed separately. Refer to [the Nvidia device plugin's documentation][nvidia] for details. #### ACL requirements for accessing the job details page in the Nomad UI Nomad 1.2.0 introduced a new UI component to display the status of `system` and `sysbatch` jobs in each client where they are running. This feature makes an API call to an endpoint that requires `node:read` ACL permission. Tokens used to access the Nomad UI will need to be updated to include this permission in order to access a job details page. This was an unintended change fixed in Nomad 1.2.4. #### HCLv2 Job Specification Parsing In previous versions of Nomad, when rendering a job specification using override variables, a warning would be returned if a variable within an override file was declared that was not found within the job specification. This behaviour differed from passing variables via the `-var` flag, which would always cause an error in the same situation. Nomad 1.2.0 fixed the behaviour consistency to always return an error by default, where an override variable was specified which was not a known variable within the job specification. In order to mitigate this change for users who wish to only be warned when this situation arises, the `-hcl-strict=false` flag can be specified. ## Nomad 1.0.11 and 1.1.5 Enterprise #### Audit log file names Audit log file naming now matches the standard log file naming introduced in 1.0.10 and 1.1.4. The audit log currently being written will no longer have a timestamp appended. ## Nomad 1.0.10 and 1.1.4 #### Log file names The [`log_file`] configuration option was not being fully respected, as the generated filename would include a timestamp. After upgrade, the active log file will always be the value defined in `log_file`, with timestamped files being created during log rotation. ## Nomad 1.0.9 and 1.1.3 #### Namespace in Job Run and Plan APIs The Job Run and Plan APIs now respect the `?namespace=...` query parameter over the namespace specified in the job itself. This matches the precedence of region and [fixes a bug where the `-namespace` flag was not respected for the `nomad run` and `nomad apply` commands.][gh-10875] For users of [`api.Client`][go-client] who want their job namespace respected, you must ensure the `Config.Namespace` field is unset. #### Docker Driver **1.1.3 only** Starting in Nomad 1.1.2, task groups with `network.mode = "bridge"` generated a hosts file in Docker containers. This generated hosts file was bind-mounted from the task directory to `/etc/hosts` within the task. In Nomad 1.1.3 the source for the bind mount was moved to the allocation directory so that it is shared between all tasks in an allocation. Please note that this change may prevent [`extra_hosts`] values from being properly set in each task when there are multiple tasks within the same group. When using `extra_hosts` with Consul Connect in `bridge` network mode, you should set the hosts values in the [`sidecar_task.config`] block instead. ## Nomad 1.1.0 #### Enterprise licenses Nomad Enterprise licenses are no longer stored in raft or synced between servers. Nomad Enterprise servers will not start without a license. There is no longer a six hour evaluation period when running Nomad Enterprise. Before upgrading, you must provide each server with a license on disk or in its environment (see the [Enterprise licensing] documentation for details). The `nomad license put` command has been removed. The `nomad license get` command is no longer forwarded to the Nomad leader, and will return the license from the specific server being contacted. Click [here](https://www.hashicorp.com/products/nomad/trial) to get a trial license for Nomad Enterprise. #### Agent Metrics API The Nomad agent metrics API now respects the [`prometheus_metrics`](https://www.nomadproject.io/docs/configuration/telemetry#prometheus_metrics) configuration value. If this value is set to `false`, which is the default value, calling `/v1/metrics?format=prometheus` will now result in a response error. #### CSI volumes The volume specification for CSI volumes has been updated to support volume creation. The `access_mode` and `attachment_mode` fields have been moved to a `capability` block that can be repeated. Existing registered volumes will be automatically modified the next time that a volume claim is updated. Volume specification files for new volumes should be updated to the format described in the [`volume create`] and [`volume register`] commands. The [`volume`] block has an `access_mode` and `attachment_mode` field that are required for CSI volumes. Jobs that use CSI volumes should be updated with these fields. #### Connect native tasks Connect native tasks running in host networking mode will now have `CONSUL_HTTP_ADDR` set automatically. Before this was only the case for bridge networking. If an operator already explicitly set `CONSUL_HTTP_ADDR` then it will not get overridden. #### Linux capabilities in exec/java Following the security [remediation][no_net_raw] in Nomad versions 0.12.12, 1.0.5, and 1.1.0-rc1, the `exec` and `java` task drivers will additionally no longer enable the following linux capabilities by default. ``` AUDIT_CONTROL AUDIT_READ BLOCK_SUSPEND DAC_READ_SEARCH IPC_LOCK IPC_OWNER LEASE LINUX_IMMUTABLE MAC_ADMIN MAC_OVERRIDE NET_ADMIN NET_BROADCAST NET_RAW SYS_ADMIN SYS_BOOT SYSLOG SYS_MODULE SYS_NICE SYS_PACCT SYS_PTRACE SYS_RAWIO SYS_RESOURCE SYS_TIME SYS_TTY_CONFIG WAKE_ALARM ``` The capabilities now enabled by default are modeled after Docker default [`linux capabilities`] (excluding `NET_RAW`). ``` AUDIT_WRITE CHOWN DAC_OVERRIDE FOWNER FSETID KILL MKNOD NET_BIND_SERVICE SETFCAP SETGID SETPCAP SETUID SYS_CHROOT ``` A new `allow_caps` plugin configuration parameter for [`exec`][allow_caps_exec] and [`java`][allow_caps_java] task drivers can be used to restrict the set of capabilities allowed for use by tasks. Tasks using the `exec` or `java` task drivers can add or remove desired linux capabilities using the [`cap_add`][cap_add_exec] and [`cap_drop`][cap_drop_exec] task configuration options. #### iptables Nomad now appends its iptables rules to the `NOMAD-ADMIN` chain instead of inserting them as the first rule. This allows better control for user-defined iptables rules but users who append rules currently should verify that their rules are being appended in the correct order. ## Nomad 1.1.0-rc1, 1.0.5, 0.12.12 Nomad versions 1.1.0-rc1, 1.0.5 and 0.12.12 change the behavior of the `docker`, `exec`, and `java` task drivers so that the [`CAP_NET_RAW`] linux capability is disabled by default. This is one of the [`linux capabilities`] that Docker itself enables by default, as this capability enables the generation of ICMP packets - used by the common `ping` utility for performing network diagnostics. When used by groups in `bridge` networking mode, the `CAP_NET_RAW` capability also exposes tasks to ARP spoofing, enabling DoS and MITM attacks against other tasks running in `bridge` networking on the same host. Operators should weigh potential impact of an upgrade on their applications against the security consequences inherit with `CAP_NET_RAW`. Typical applications using `tcp` or `udp` based networking should not be affected. This is the sole change for Nomad 1.0.5 and 0.12.12, intended to provide better task network isolation by default. Users of the `docker` driver can restore the previous behavior by configuring the [`allow_caps`] driver configuration option to explicitly enable the `CAP_NET_RAW` capability. ```hcl plugin "docker" { config { allow_caps = [ "CHOWN", "DAC_OVERRIDE", "FSETID", "FOWNER", "MKNOD", "SETGID", "SETUID", "SETFCAP", "SETPCAP", "NET_BIND_SERVICE", "SYS_CHROOT", "KILL", "AUDIT_WRITE", "NET_RAW", ] } } ``` An upcoming version of Nomad will include similar configuration options for the `exec` and `java` task drivers. This change is limited to `docker`, `exec`, and `java` driver plugins. It does not affect the Nomad server. This only affects Nomad clients running Linux, with tasks using `bridge` networking and one of these task drivers, or third-party plugins which relied on the shared Nomad executor library. Upgrading a Nomad client to 1.0.5 or 0.12.12 will not restart existing tasks. As such, processes from existing `docker`, `exec`, or `java` tasks will need to be manually restarted (using `alloc stop` or another mechanism) in order to be fully isolated. ## Nomad 1.0.3, 0.12.10 Nomad versions 1.0.3 and 0.12.10 change the behavior of the `exec` and `java` drivers so that tasks are isolated in their own PID and IPC namespaces. As a result, the process launched by these drivers will be PID 1 in the namespace. This has [significant impact](https://man7.org/linux/man-pages/man7/pid_namespaces.7.html) on the treatment of a process by the Linux kernel. Furthermore, tasks in the same allocation will no longer be able to coordinate using signals, SystemV IPC objects, or POSIX message queues. Operators should weigh potential impact of an upgrade on their applications against the security consequences inherent in using the host namespaces. This is the sole change for Nomad 1.0.3, intended to provide better process isolation by default. An upcoming version of Nomad will include options for configuring this behavior. This change is limited to the `exec` and `java` driver plugins. It does not affect the Nomad server. This only affect Nomad clients running on Linux, using the `exec` or `java` drivers or third-party driver plugins which relied on the shared Nomad executor library. Upgrading a Nomad client to 1.0.3 or 0.12.10 will not restart existing tasks. As such, processes from existing `exec`/`java` tasks will need to be manually restarted (using `alloc stop` or another mechanism) in order to be fully isolated. ## Nomad 1.0.2 #### Dynamic secrets trigger template changes on client restart Nomad 1.0.2 changed the behavior of template `change_mode` triggers when a client node restarts. In Nomad 1.0.1 and earlier, the first rendering of a template after a client restart would not trigger the `change_mode`. For dynamic secrets such as the Vault PKI secrets engine, this resulted in the secret being updated but not restarting or signalling the task. When the secret's lease expired at some later time, the task workload might fail because of the stale secret. For example, a web server's SSL certificate would be expired and browsers would be unable to connect. In Nomad 1.0.2, when a client node is restarted any task with Vault secrets that are generated or have expired will have its `change_mode` triggered. If `change_mode = "restart"` this will result in the task being restarted, to avoid the task failing unexpectedly at some point in the future. This change only impacts tasks using dynamic Vault secrets engines such as [PKI][pki], or when secrets are rotated. Secrets that don't change in Vault will not trigger a `change_mode` on client restart. ## Nomad 1.0.1 #### Envoy worker threads Nomad v1.0.0 changed the default behavior around the number of worker threads created by the Envoy when being used as a sidecar for Consul Connect. In Nomad v1.0.1, the same default setting of [`--concurrency=1`][envoy_concurrency] is set for Envoy when used as a Connect gateway. As before, the [`meta.connect.proxy_concurrency`][proxy_concurrency] property can be set in client configuration to override the default value. ## Nomad 1.0.0 ### HCL2 for Job specification Nomad v1.0.0 adopts HCL2 for parsing the job spec. HCL2 extends HCL with more expression and reuse support, but adds some stricter schema for HCL blocks (a.k.a. stanzas). Check [HCL](/docs/job-specification/hcl2) for more details. ### Signal used when stopping Docker tasks When stopping tasks running with the Docker task driver, Nomad documents that a `SIGTERM` will be issued (unless configured with `kill_signal`). However, recent versions of Nomad would issue `SIGINT` instead. Starting again with Nomad v1.0.0 `SIGTERM` will be sent by default when stopping Docker tasks. ### Deprecated metrics have been removed Nomad v0.7.0 added supported for tagged metrics and deprecated untagged metrics. There was support for configuring backwards-compatible metrics. This support has been removed with v1.0.0, and all metrics will be emitted with tags. ### Null characters in region, datacenter, job name/ID, task group name, and task names Starting with Nomad v1.0.0, jobs will fail validation if any of the following contain null character: the job ID or name, the task group name, or the task name. Any jobs meeting this requirement should be modified before an update to v1.0.0. Similarly, client and server config validation will prohibit either the region or the datacenter from containing null characters. ### EC2 CPU characteristics may be different Starting with Nomad v1.0.0, the AWS fingerprinter uses data derived from the official AWS EC2 API to determine default CPU performance characteristics, including core count and core speed. This data should be accurate for each instance type per region. Previously, Nomad used a hand-made lookup table that was not region aware and may have contained inaccurate or incomplete data. As part of this change, the AWS fingerprinter no longer sets the `cpu.modelname` attribute. As before, `cpu_total_compute` can be used to override the discovered CPU resources available to the Nomad client. ### Inclusive language Starting with Nomad v1.0.0, the terms `blacklist` and `whitelist` have been deprecated from client configuration and driver configuration. The existing configuration values are permitted but will be removed in a future version of Nomad. The specific configuration values replaced are: - Client `driver.blacklist` is replaced with `driver.denylist`. - Client `driver.whitelist` is replaced with `driver.allowlist`. - Client `env.blacklist` is replaced with `env.denylist`. - Client `fingerprint.blacklist` is replaced with `fingerprint.denylist`. - Client `fingerprint.whitelist` is replaced with `fingerprint.allowlist`. - Client `user.blacklist` is replaced with `user.denylist`. - Client `template.function_blacklist` is replaced with `template.function_denylist`. - Docker driver `docker.caps.whitelist` is replaced with `docker.caps.allowlist`. ### Consul Connect Nomad 1.0's Consul Connect integration works best with Consul 1.9 or later. The ideal upgrade path is: 1. Create a new Nomad client image with Nomad 1.0 and Consul 1.9 or later. 2. Add new hosts based on the image. 3. [Drain][drain-cli] and shutdown old Nomad client nodes. While inplace upgrades and older versions of Consul are supported by Nomad 1.0, Envoy proxies will drop and stop accepting connections while the Nomad agent is restarting. Nomad 1.0 with Consul 1.9 do not have this limitation. #### Envoy proxy versions Nomad v1.0.0 changes the behavior around the selection of Envoy version used for Connect sidecar proxies. Previously, Nomad always defaulted to Envoy v1.11.2 if neither the `meta.connect.sidecar_image` parameter or `sidecar_task` stanza were explicitly configured. Likewise the same version of Envoy would be used for Connect ingress gateways if `meta.connect.gateway_image` was unset. Starting with Nomad v1.0.0, each Nomad Client will query Consul for a list of supported Envoy versions. Nomad will make use of the latest version of Envoy supported by the Consul agent when launching Envoy as a Connect sidecar proxy. If the version of the Consul agent is older than v1.7.8, v1.8.4, or v1.9.0, Nomad will fallback to the v1.11.2 version of Envoy. As before, if the `meta.connect.sidecar_image`, `meta.connect.gateway_image`, or `sidecar_task` stanza are set, those settings take precedence. When upgrading Nomad Clients from a previous version to v1.0.0 and above, it is recommended to also upgrade the Consul agents to v1.7.8, 1.8.4, or v1.9.0 or newer. Upgrading Nomad and Consul to versions that support the new behavior while also doing a full [node drain][] at the time of the upgrade for each node will ensure Connect workloads are properly rescheduled onto nodes in such a way that the Nomad Clients, Consul agents, and Envoy sidecar tasks maintain compatibility with one another. #### Envoy worker threads Nomad v1.0.0 changes the default behavior around the number of worker threads created by the Envoy sidecar proxy when using Consul Connect. Previously, the Envoy [`--concurrency`][envoy_concurrency] argument was left unset, which caused Envoy to spawn as many worker threads as logical cores available on the CPU. The `--concurrency` value now defaults to `1` and can be configured by setting the [`meta.connect.proxy_concurrency`][proxy_concurrency] property in client configuration. ## Nomad 0.12.8 ### Docker volume mounts Nomad 0.12.8 includes security fixes for the handling of Docker volume mounts: - The `docker.volumes.enabled` flag now defaults to `false` as documented. - Docker driver mounts of type "volume" (but not "bind") were not sandboxed and could mount arbitrary locations from the client host. The `docker.volumes.enabled` configuration will now disable Docker mounts with type "volume" when set to `false` (the default). This change Docker impacts jobs that use a `mounts` with type "volume", as shown below. This job will fail when placed unless `docker.volumes.enabled = true`. ```hcl mounts = [ { type = "volume" target = "/path/in/container" source = "docker_volume" volume_options = { driver_config = { name = "local" options = [ { device = "/" o = "ro,bind" type = "ext4" } ] } } } ] ``` ## Nomad 0.12.6 ### Artifact and Template Paths Nomad 0.12.6 includes security fixes for privilege escalation vulnerabilities in handling of job `template` and `artifact` stanzas: - The `template.source` and `template.destination` fields are now protected by the file sandbox introduced in 0.9.6. These paths are now restricted to fall inside the task directory by default. An operator can opt-out of this protection with the [`template.disable_file_sandbox`][] field in the client configuration. - The paths for `template.source`, `template.destination`, and `artifact.destination` are validated on job submission to ensure the paths do not escape the file sandbox. It was possible to use interpolation to bypass this validation. The client now interpolates the paths before checking if they are in the file sandbox. ~> **Warning:** Due to a [bug][gh-9148] in Nomad v0.12.6, the `template.destination` and `artifact.destination` paths do not support absolute paths, including the interpolated `NOMAD_SECRETS_DIR`, `NOMAD_TASK_DIR`, and `NOMAD_ALLOC_DIR` variables. This bug is fixed in v0.12.9. To work around the bug, use a relative path. ## Nomad 0.12.0 ### `mbits` and Task Network Resource deprecation Starting in Nomad 0.12.0 the `mbits` field of the network resource block has been deprecated and is no longer considered when making scheduling decisions. This is in part because we felt that `mbits` didn't accurately account network bandwidth as a resource. Additionally the use of the `network` block inside of a task's `resource` block is also deprecated. Users are advised to move their `network` block to the `group` block. Recent networking features have only been added to group based network configuration. If any usecase or feature which was available with task network resource is not fulfilled with group network configuration, please open an issue detailing the missing capability. Additionally, the `docker` driver's `port_map` configuration is deprecated in lieu of the `ports` field. ### Enterprise Licensing Enterprise binaries for Nomad are now publicly available via [releases.hashicorp.com](https://releases.hashicorp.com/nomad/). By default all enterprise features are enabled for 6 hours. During that time enterprise users should apply their license with the [`nomad license put ...`](https://developer.hashicorp.com/nomad/docs/v1.0.x/commands/license/put) command. Once the 6 hour demonstration period expires, Nomad will shutdown. If restarted Nomad will shutdown in a very short amount of time unless a valid license is applied. ~> **Warning:** Due to a [bug][gh-8457] in Nomad v0.12.0, existing clusters that are upgraded will **not** have 6 hours to apply a license. The minimal grace period should be sufficient to apply a valid license, but enterprise users are encouraged to delay upgrading until Nomad v0.12.1 is released and fixes the issue. ### Docker access host filesystem Nomad 0.12.0 disables Docker tasks access to the host filesystem, by default. Prior to Nomad 0.12, Docker tasks may mount and then manipulate any host file and may pose a security risk. Operators now must explicitly allow tasks to access host filesystem. [Host Volumes](/docs/configuration/client#host_volume-stanza) provide a fine tune access to individual paths. To restore pre-0.12.0 behavior, you can enable [Docker `volume`](/docs/drivers/docker#enabled-1) to allow binding host paths, by adding the following to the nomad client config file: ```hcl plugin "docker" { config { volumes { enabled = true } } } ``` ### QEMU images Nomad 0.12.0 restricts the paths the QEMU tasks can load an image from. A QEMU task may download an image to the allocation directory to load. But images outside the allocation directories must be explicitly allowed by operators in the client agent configuration file. For example, you may allow loading QEMU images from `/mnt/qemu-images` by adding the following to the agent configuration file: ```hcl plugin "qemu" { config { image_paths = ["/mnt/qemu-images"] } } ``` ## Nomad 0.11.7 ### Docker volume mounts Nomad 0.11.7 includes a security fix for the handling of Docker volume mounts. Docker driver mounts of type "volume" (but not "bind") were not sandboxed and could mount arbitrary locations from the client host. The `docker.volumes.enabled` configuration will now disable Docker mounts with type "volume" when set to `false`. This change Docker impacts jobs that use a `mounts` with type "volume", as shown below. This job will fail when placed unless `docker.volumes.enabled = true`. ```hcl mounts = [ { type = "volume" target = "/path/in/container" source = "docker_volume" volume_options = { driver_config = { name = "local" options = [ { device = "/" o = "ro,bind" type = "ext4" } ] } } } ] ``` ## Nomad 0.11.5 ### Artifact and Template Paths Nomad 0.11.5 includes backported security fixes for privilege escalation vulnerabilities in handling of job `template` and `artifact` stanzas: - The `template.source` and `template.destination` fields are now protected by the file sandbox introduced in 0.9.6. These paths are now restricted to fall inside the task directory by default. An operator can opt-out of this protection with the [`template.disable_file_sandbox`](/docs/configuration/client#template-parameters) field in the client configuration. - The paths for `template.source`, `template.destination`, and `artifact.destination` are validated on job submission to ensure the paths do not escape the file sandbox. It was possible to use interpolation to bypass this validation. The client now interpolates the paths before checking if they are in the file sandbox. ~> **Warning:** Due to a [bug][gh-9148] in Nomad v0.11.5, the `template.destination` and `artifact.destination` paths do not support absolute paths, including the interpolated `NOMAD_SECRETS_DIR`, `NOMAD_TASK_DIR`, and `NOMAD_ALLOC_DIR` variables. This bug is fixed in v0.11.6. To work around the bug, use a relative path. ## Nomad 0.11.3 Nomad 0.11.3 fixes a critical bug causing the nomad agent to become unresponsive. The issue is due to a [Go 1.14.1 runtime bug](https://github.com/golang/go/issues/38023) and affects Nomad 0.11.1 and 0.11.2. ## Nomad 0.11.2 ### Scheduler Scoring Changes Prior to Nomad 0.11.2 the scheduler algorithm used a [node's reserved resources][reserved] incorrectly during scoring. The result of this bug was that scoring biased in favor of nodes with reserved resources vs nodes without reserved resources. Placements will be more correct but slightly different in v0.11.2 vs earlier versions of Nomad. Operators do _not_ need to take any actions as the impact of the bug fix will only minimally affect scoring. Feasibility (whether a node is capable of running a job at all) is _not_ affected. ### Periodic Jobs and Daylight Saving Time Nomad 0.11.2 fixed a long outstanding bug affecting periodic jobs that are scheduled to run during Daylight Saving Time transitions. Nomad 0.11.2 provides a more defined behavior: Nomad evaluates the cron expression with respect to specified time zone during transition. A 2:30am nightly job with `America/New_York` time zone will not run on the day daylight saving time starts; similarly, a 1:30am nightly job will run twice on the day daylight saving time ends. See the [Daylight Saving Time][dst] documentation for details. ## Nomad 0.11.0 ### client.template: `vault_grace` deprecation Nomad 0.11.0 updates [consul-template](https://github.com/hashicorp/consul-template) to v0.24.1. This library deprecates the [`vault_grace`][vault_grace] option for templating included in Nomad. The feature has been ignored since Vault 0.5 and as long as you are running a more recent version of Vault, you can safely remove `vault_grace` from your Nomad jobs. ### Rkt Task Driver Removed The `rkt` task driver has been deprecated and removed from Nomad. While the code is available in an external repository, , it will not be maintained as `rkt` is [no longer being developed upstream](https://github.com/rkt/rkt). We encourage all `rkt` users to find a new task driver as soon as possible. ## Nomad 0.10.8 ### Docker volume mounts Nomad 0.10.8 includes a security fix for the handling of Docker volume mounts. Docker driver mounts of type "volume" (but not "bind") were not sandboxed and could mount arbitrary locations from the client host. The `docker.volumes.enabled` configuration will now disable Docker mounts with type "volume" when set to `false`. This change Docker impacts jobs that use a `mounts` with type "volume", as shown below. This job will fail when placed unless `docker.volumes.enabled = true`. ```hcl mounts = [ { type = "volume" target = "/path/in/container" source = "docker_volume" volume_options = { driver_config = { name = "local" options = [ { device = "/" o = "ro,bind" type = "ext4" } ] } } } ] ``` ## Nomad 0.10.6 ### Artifact and Template Paths Nomad 0.10.6 includes backported security fixes for privilege escalation vulnerabilities in handling of job `template` and `artifact` stanzas: - The `template.source` and `template.destination` fields are now protected by the file sandbox introduced in 0.9.6. These paths are now restricted to fall inside the task directory by default. An operator can opt-out of this protection with the [`template.disable_file_sandbox`](/docs/configuration/client#template-parameters) field in the client configuration. - The paths for `template.source`, `template.destination`, and `artifact.destination` are validated on job submission to ensure the paths do not escape the file sandbox. It was possible to use interpolation to bypass this validation. The client now interpolates the paths before checking if they are in the file sandbox. ~> **Warning:** Due to a [bug][gh-9148] in Nomad v0.10.6, the `template.destination` and `artifact.destination` paths do not support absolute paths, including the interpolated `NOMAD_SECRETS_DIR`, `NOMAD_TASK_DIR`, and `NOMAD_ALLOC_DIR` variables. This bug is fixed in v0.10.7. To work around the bug, use a relative path. ## Nomad 0.10.4 ### Same-Node Scheduling Penalty Removed Nomad 0.10.4 includes a fix to the scheduler that removes the same-node penalty for allocations that have not previously failed. In earlier versions of Nomad, the node where an allocation was running was penalized from receiving updated versions of that allocation, resulting in a higher chance of the allocation being placed on a new node. This was changed so that the penalty only applies to nodes where the previous allocation has failed or been rescheduled, to reduce the risk of correlated failures on a host. Scheduling weighs a number of factors, but this change should reduce movement of allocations that are being updated from a healthy state. You can view the placement metrics for an allocation with `nomad alloc status -verbose`. ### Additional Environment Variable Filtering Nomad will by default prevent certain environment variables set in the client process from being passed along into launched tasks. The `CONSUL_HTTP_TOKEN` environment variable has been added to the default list. More information can be found in the `env.blacklist` [configuration](/docs/configuration/client#env-blacklist) . ## Nomad 0.10.3 ### mTLS Certificate Validation Nomad 0.10.3 includes a fix for a privilege escalation vulnerability in validating TLS certificates for RPC with mTLS. Nomad RPC endpoints validated that TLS client certificates had not expired and were signed by the same CA as the Nomad node, but did not correctly check the certificate's name for the role and region as described in the [Securing Nomad with TLS][tls-guide] guide. This allows trusted operators with a client certificate signed by the CA to send RPC calls as a Nomad client or server node, bypassing access control and accessing any secrets available to a client. Nomad clusters configured for mTLS following the [Securing Nomad with TLS][tls-guide] guide or the [Vault PKI Secrets Engine Integration][tls-vault-guide] guide should already have certificates that will pass validation. Before upgrading to Nomad 0.10.3, operators using mTLS with `verify_server_hostname = true` should confirm that the common name or SAN of all Nomad client node certs is `client..nomad`, and that the common name or SAN of all Nomad server node certs is `server..nomad`. ### Connection Limits Added Nomad 0.10.3 introduces the [limits][] agent configuration parameters for mitigating denial of service attacks from users who are not authenticated via mTLS. The default limits stanza is: ```hcl limits { https_handshake_timeout = "5s" http_max_conns_per_client = 100 rpc_handshake_timeout = "5s" rpc_max_conns_per_client = 100 } ``` If your Nomad agent's endpoints are protected from unauthenticated users via other mechanisms these limits may be safely disabled by setting them to `0`. However the defaults were chosen to be safe for a wide variety of Nomad deployments and may protect against accidental abuses of the Nomad API that could cause unintended resource usage. ## Nomad 0.10.2 ### Preemption Panic Fixed Nomad 0.9.7 and 0.10.2 fix a [server crashing bug][gh-6787] present in scheduler preemption since 0.9.0. Users unable to immediately upgrade Nomad can [disable preemption][preemption-api] to avoid the panic. ### Dangling Docker Container Cleanup Nomad 0.10.2 addresses an issue occurring in heavily loaded clients, where containers are started without being properly managed by Nomad. Nomad 0.10.2 introduced a reaper that detects and kills such containers. Operators may opt to run reaper in a dry-mode or disabling it through a client config. For more information, see [Docker Dangling containers][dangling-containers]. ## Nomad 0.10.0 ### Deployments Nomad 0.10 enables rolling deployments for service jobs by default and adds a default update stanza when a service job is created or updated. This does not affect jobs with an update stanza. In pre-0.10 releases, when updating a service job without an update stanza, all existing allocations are stopped while new allocations start up, and this may cause a service degradation or an outage. You can regain this behavior and disable deployments by setting `max_parallel` to 0. For more information, see [`update` stanza][update]. ## Nomad 0.9.5 ### Template Rendering Nomad 0.9.5 includes security fixes for privilege escalation vulnerabilities in handling of job `template` stanzas: - The client host's environment variables are now cleaned before rendering the template. If a template includes the `env` function, the job should include an [`env`](/docs/job-specification/env) stanza to allow access to the variable in the template. - The `plugin` function is no longer permitted by default and will raise an error if used in a template. Operator can opt-in to permitting this function with the new [`template.function_blacklist`](/docs/configuration/client#template-parameters) field in the client configuration. - The `file` function has been changed to restrict paths to fall inside the task directory by default. Paths that used the `NOMAD_TASK_DIR` environment variable to prefix file paths should work unchanged. Relative paths or symlinks that point outside the task directory will raise an error. An operator can opt-out of this protection with the new [`template.disable_file_sandbox`](/docs/configuration/client#template-parameters) field in the client configuration. ## Nomad 0.9.0 ### Preemption Nomad 0.9 adds preemption support for system jobs. If a system job is submitted that has a higher priority than other running jobs on the node, and the node does not have capacity remaining, Nomad may preempt those lower priority allocations to place the system job. See [preemption][preemption] for more details. ### Task Driver Plugins All task drivers have become [plugins][plugins] in Nomad 0.9.0. There are two user visible differences between 0.8 and 0.9 drivers: - [LXC][lxc] is now community supported and distributed independently. - Task driver [`config`][task-config] stanzas are no longer validated by the [`nomad job validate`][validate] command. This is a regression that will be fixed in a future release. There is a new method for client driver configuration options, but existing `client.options` settings are supported in 0.9. See [plugin configuration][plugin-stanza] for details. #### LXC LXC is now an external plugin and must be installed separately. See [the LXC driver's documentation][lxc] for details. ### Structured Logging Nomad 0.9.0 switches to structured logging. Any log processing on the pre-0.9 log output will need to be updated to match the structured output. Structured log lines have the format: ``` # [] : : = ... 2019-01-29T05:52:09.221Z [INFO ] client.plugin: starting plugin manager: plugin-type=device ``` Values containing whitespace will be quoted: ``` ... starting plugin: task=redis args="[/opt/gopath/bin/nomad logmon]" ``` ### HCL2 Transition Nomad 0.9.0 begins a transition to [HCL2][hcl2], the next version of the HashiCorp configuration language. While Nomad has begun integrating HCL2, users will need to continue to use HCL1 in Nomad 0.9.0 as the transition is incomplete. If you interpolate variables in your [`task.config`][task-config] containing consecutive dots in their name, you will need to change your job specification to use the `env` map. See the following example: ```hcl env { # Note the multiple consecutive dots image...version = "3.2" # Valid in both v0.8 and v0.9 image.version = "3.2" } # v0.8 task config stanza: task { driver = "docker" config { image = "redis:${image...version}" } } # v0.9 task config stanza: task { driver = "docker" config { image = "redis:${env["image...version"]}" } } ``` This only affects users who interpolate unusual variables with multiple consecutive dots in their task `config` stanza. All other interpolation is unchanged. Since HCL2 uses dotted object notation for interpolation users should transition away from variable names with multiple consecutive dots. ### Downgrading clients Due to the large refactor of the Nomad client in 0.9, downgrading to a previous version of the client after upgrading it to Nomad 0.9 is not supported. To downgrade safely, users should erase the Nomad client's data directory. ### `port_map` Environment Variable Changes Before Nomad 0.9.0 ports mapped via a task driver's `port_map` stanza could be interpolated via the `NOMAD_PORT_