a84d2de9be
Co-authored-by: Geoffrey Grosenbach <26+topfunky@users.noreply.github.com> Co-authored-by: Anthony <russo555@gmail.com> Co-authored-by: Ashlee Boyer <ashlee.boyer@hashicorp.com> Co-authored-by: Ashlee M Boyer <43934258+ashleemboyer@users.noreply.github.com> Co-authored-by: HashiBot <62622282+hashibot-web@users.noreply.github.com> Co-authored-by: Kevin Wang <kwangsan@gmail.com>
105 lines
4.8 KiB
Plaintext
105 lines
4.8 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: Frequently Asked Questions
|
|
description: Frequently asked questions and answers for Nomad
|
|
---
|
|
|
|
# Frequently Asked Questions
|
|
|
|
## Q: What is Checkpoint? / Does Nomad call home?
|
|
|
|
Nomad makes use of a HashiCorp service called [Checkpoint](https://checkpoint.hashicorp.com)
|
|
which is used to check for updates and critical security bulletins.
|
|
Only anonymous information, which cannot be used to identify the user or host, is
|
|
sent to Checkpoint. An anonymous ID is sent which helps de-duplicate warning messages.
|
|
This anonymous ID can be disabled. Using the Checkpoint service is optional and can be disabled.
|
|
|
|
See [`disable_anonymous_signature`](/docs/configuration#disable_anonymous_signature)
|
|
and [`disable_update_check`](/docs/configuration#disable_update_check).
|
|
|
|
## Q: Is Nomad eventually or strongly consistent?
|
|
|
|
Nomad makes use of both a [consensus protocol](/docs/concepts/consensus) and
|
|
a [gossip protocol](/docs/concepts/gossip). The consensus protocol is strongly
|
|
consistent, and is used for all state replication and scheduling. The gossip protocol
|
|
is used to manage the addresses of servers for automatic clustering and multi-region
|
|
federation. This means all data that is managed by Nomad is strongly consistent.
|
|
|
|
## Q: Is Nomad's `datacenter` parameter the same as Consul's?
|
|
|
|
No. For those familiar with Consul, [Consul's notion of a
|
|
datacenter][consul_dc] is more equivalent to a [Nomad region][nomad_region].
|
|
Nomad supports grouping nodes into multiple datacenters, which should reflect
|
|
nodes being colocated, while being managed by a single set of Nomad servers.
|
|
|
|
Consul on the other hand does not have this two-tier approach to servers and
|
|
agents and instead [relies on federation to create larger logical
|
|
clusters][consul_fed].
|
|
|
|
## Q: What is "bootstrapping" a Nomad cluster? ((#bootstrapping))
|
|
|
|
Bootstrapping is the process when a Nomad cluster elects its first leader
|
|
and writes the initial cluster state to that leader's state store. Bootstrapping
|
|
will not occur until at least a given number of servers, defined by
|
|
[`bootstrap_expect`], have connected to each other. Once this process has
|
|
completed, the cluster is said to be bootstrapped and is ready to use.
|
|
|
|
Certain configuration options are only used to influence the creation of the
|
|
initial cluster state during bootstrapping and are not consulted again so long
|
|
as the state data remains intact. These typically are values that must be
|
|
consistent across server members. For example, the [`default_scheduler_config`]
|
|
option allows an operator to set the SchedulerConfig to non-default values
|
|
during this bootstrap process rather than requiring an immediate call to the API
|
|
once the cluster is up and running.
|
|
|
|
If the state is completely destroyed, whether intentionally or accidentally, on
|
|
all of the Nomad servers in the same outage, the cluster will re-bootstrap based
|
|
on the Nomad defaults and any configuration present that impacts the bootstrap
|
|
process.
|
|
|
|
## Q: How to connect to my host network when using Docker Desktop (Windows and MacOS)?
|
|
|
|
Since Docker is based on Linux-native technologies, Docker Desktop for Windows
|
|
and MacOS uses a small Linux virtual machine to run containers. This extra step
|
|
adds a layer of indirection between the network of your host (the computer you
|
|
are currently using) and the network of the VM running your containers.
|
|
|
|
This means that, by default, your Docker tasks will not be able to access
|
|
endpoints that are available in your host network, such as a local Consul agent.
|
|
|
|
In order to properly setup this connection you will need to explicitly bind
|
|
the Nomad client to a non-loopback network interface, and anything else you
|
|
would like to access must also be in the same interface.
|
|
|
|
On Windows, we recommend you to start with the [WSL2 backend for Docker
|
|
Desktop][wsl2-docker]. Once you are more familiarized with Nomad you can start
|
|
running it natively.
|
|
|
|
To use the network named `en0` that has the IP address `192.168.0.10`, you can
|
|
start Nomad with this command.
|
|
|
|
```shell-session
|
|
$ sudo nomad agent -dev -bind=0.0.0.0 -network-interface=en0
|
|
```
|
|
|
|
To start Consul in the same network, you can run this command.
|
|
|
|
```shell-session
|
|
$ consul agent -dev -client=0.0.0.0 -bind=192.168.0.10
|
|
```
|
|
|
|
Now your services will be registered in Consul using the right IP and your
|
|
tasks will be able to reach each other. To access your tasks from your host
|
|
machine you will need to use the network interface IP address.
|
|
|
|
```shell-session
|
|
$ curl http://192.168.0.10:8080
|
|
```
|
|
|
|
[consul_dc]: https://www.consul.io/docs/agent/config/config-files#datacenter
|
|
[consul_fed]: https://learn.hashicorp.com/tutorials/consul/federarion-gossip-wan
|
|
[nomad_region]: /docs/configuration#datacenter
|
|
[`bootstrap_expect`]: /docs/configuration/server#bootstrap_expect
|
|
[`default_scheduler_config`]: /docs/configuration/server#default_scheduler_config
|
|
[wsl2-docker]: https://docs.docker.com/docker-for-windows/wsl/
|