64b1cafa57
Current efs driver does not support telling it if its a `node` or a `controller`, and it will not print any error it will just ignore all other parameters then:( So this will result in endpoint being `/tmp/csi.sock` and not `/csi/csi.sock` which will in turn break nomad/csi integration. Also I changed the latest image tag to v1.3.2 to make sure anybody copy pasting this example is sure that it will work. Tested on nomad 1.1.2
127 lines
4.2 KiB
Plaintext
127 lines
4.2 KiB
Plaintext
---
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layout: docs
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page_title: csi_plugin Stanza - Job Specification
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description: >-
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The "csi_plugin" stanza allows the task to specify it provides a
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Container Storage Interface plugin to the cluster.
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---
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# `csi_plugin` Stanza
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<Placement groups={['job', 'group', 'task', 'volume']} />
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The "csi_plugin" stanza allows the task to specify it provides a
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Container Storage Interface plugin to the cluster. Nomad will
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automatically register the plugin so that it can be used by other jobs
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to claim [volumes][csi_volumes].
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```hcl
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csi_plugin {
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id = "csi-hostpath"
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type = "monolith"
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mount_dir = "/csi"
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}
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```
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## `csi_plugin` Parameters
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- `id` `(string: <required>)` - This is the ID for the plugin. Some
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plugins will require both controller and node plugin types (see
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below); you need to use the same ID for both so that Nomad knows they
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belong to the same plugin.
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- `type` `(string: <required>)` - One of `node`, `controller`, or
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`monolith`. Each plugin supports one or more types. Each Nomad
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client node where you want to mount a volume will need a `node`
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plugin instance. Some plugins will also require one or more
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`controller` plugin instances to communicate with the storage
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provider's APIs. Some plugins can serve as both `controller` and
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`node` at the same time, and these are called `monolith`
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plugins. Refer to your CSI plugin's documentation.
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- `mount_dir` `(string: <required>)` - The directory path inside the
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container where the plugin will expect a Unix domain socket for
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bidirectional communication with Nomad.
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~> **Note:** Plugins running as `node` or `monolith` require root
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privileges (or `CAP_SYS_ADMIN` on Linux) to mount volumes on the
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host. With the Docker task driver, you can use the `privileged = true`
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configuration, but no other default task drivers currently have this
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option.
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## Recommendations for Deploying CSI Plugins
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CSI plugins run as Nomad jobs but after mounting the volume are not in the
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data path for the volume. Jobs that mount volumes write and read directly to
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the volume via a bind-mount and there is no communication between the job and
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the CSI plugin. But when an allocation that mounts a volume stops, Nomad will
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need to communicate with the plugin on that allocation's node to unmount the
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volume. This has implications on how to deploy CSI plugins:
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* During node drains, jobs that claim volumes must be moved before the `node`
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or `monolith` plugin for those volumes. You should run `node` or `monolith`
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plugins as [`system`][system] jobs and use the `-ignore-system` flag on
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`nomad node drain` to ensure that the plugins are running while the node is
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being drained.
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* Only one plugin instance of a given plugin ID and type (controller or node)
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should be deployed on any given client node. Use a constraint as shown
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below.
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* Some plugins will create volumes only in the same location as the
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plugin. For example, the AWS EBS plugin will create and mount volumes only
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within the same Availability Zone. You should deploy these plugins with a
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unique-per-AZ `plugin_id` to allow Nomad to place allocations in the correct
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AZ.
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## `csi_plugin` Examples
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```hcl
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job "plugin-efs" {
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datacenters = ["dc1"]
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# you can run node plugins as service jobs as well, but running
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# as a system job ensures all nodes in the DC have a copy.
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type = "system"
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# only one plugin of a given type and ID should be deployed on
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# any given client node
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constraint {
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operator = "distinct_hosts"
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value = true
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}
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group "nodes" {
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task "plugin" {
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driver = "docker"
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config {
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image = "amazon/aws-efs-csi-driver:v.1.3.2"
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args = [
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"--endpoint=unix://csi/csi.sock",
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"--logtostderr",
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"--v=5",
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]
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# all CSI node plugins will need to run as privileged tasks
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# so they can mount volumes to the host. controller plugins
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# do not need to be privileged.
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privileged = true
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}
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csi_plugin {
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id = "aws-efs0"
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type = "node"
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mount_dir = "/csi" # this path /csi matches the --endpoint
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# argument for the container
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}
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}
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}
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}
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```
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[csi]: https://github.com/container-storage-interface/spec
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[csi_volumes]: /docs/job-specification/volume
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[system]: /docs/schedulers#system
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