mirror of
https://github.com/kemko/nomad.git
synced 2026-01-03 17:05:43 +03:00
9d5c7b5d94
In #12324 we made it so that plugins wait until the node drain is complete, as we do for system jobs. But we neglected to mark the node drain as complete once only plugins (or system jobs) remaining, which means that the node drain is left in a draining state until the `deadline` time expires. This was incorrectly documented as expected behavior in #12324.
150 lines
5.4 KiB
Plaintext
150 lines
5.4 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: 'Commands: node drain'
|
|
description: |
|
|
The node drain command is used to configure a node's drain strategy.
|
|
---
|
|
|
|
# Command: node drain
|
|
|
|
The `node drain` command is used to toggle drain mode on a given node. Drain
|
|
mode prevents any new tasks from being allocated to the node, and begins
|
|
migrating all existing allocations away. Allocations will be migrated according
|
|
to their [`migrate`][migrate] stanza until the drain's deadline is reached.
|
|
|
|
By default the `node drain` command blocks until a node is done draining and
|
|
all allocations have terminated. Canceling the `node drain` command _will not_
|
|
cancel the drain. Drains may be canceled by using the `-disable` parameter
|
|
below.
|
|
|
|
When draining more than one node at a time, it is recommended you first
|
|
disable [scheduling eligibility][eligibility] on all nodes that will be
|
|
drained. For example if you are decommissioning an entire class of nodes,
|
|
first run `node eligibility -disable` on all of their node IDs, and then run
|
|
`node drain -enable`. This will ensure allocations drained from the first node
|
|
are not placed on another node about to be drained.
|
|
|
|
The [node status] command compliments this nicely by providing the current drain
|
|
status of a given node.
|
|
|
|
See the [Workload Migration guide] for detailed examples of node draining.
|
|
|
|
## Usage
|
|
|
|
```plaintext
|
|
nomad node drain [options] <node>
|
|
```
|
|
|
|
A `-self` flag can be used to drain the local node. If this is not supplied, a
|
|
node ID or prefix must be provided. If there is an exact match, the drain mode
|
|
will be adjusted for that node. Otherwise, a list of matching nodes and
|
|
information will be displayed.
|
|
|
|
It is also required to pass one of `-enable` or `-disable`, depending on which
|
|
operation is desired.
|
|
|
|
If ACLs are enabled, this option requires a token with the 'node:write'
|
|
capability.
|
|
|
|
## General Options
|
|
|
|
@include 'general_options_no_namespace.mdx'
|
|
|
|
## Drain Options
|
|
|
|
- `-enable`: Enable node drain mode.
|
|
|
|
- `-disable`: Disable node drain mode.
|
|
|
|
- `-deadline`: Set the deadline by which all allocations must be moved off the
|
|
node. Remaining allocations after the deadline are force removed from the
|
|
node. Defaults to 1 hour.
|
|
|
|
- `-detach`: Return immediately instead of entering monitor mode.
|
|
|
|
- `-monitor`: Enter monitor mode directly without modifying the drain status.
|
|
|
|
- `-force`: Force remove allocations off the node immediately.
|
|
|
|
- `-no-deadline`: No deadline allows the allocations to drain off the node
|
|
without being force stopped after a certain deadline.
|
|
|
|
- `-ignore-system`: Ignore system allows the drain to complete without
|
|
stopping system job allocations. By default system jobs (and CSI
|
|
plugins) are stopped last.
|
|
|
|
- `-keep-ineligible`: Keep ineligible will maintain the node's scheduling
|
|
ineligibility even if the drain is being disabled. This is useful when an
|
|
existing drain is being cancelled but additional scheduling on the node is not
|
|
desired.
|
|
|
|
- `-m`: Message for the drain update operation. Registered in drain metadata as
|
|
`"message"` during drain enable and `"cancel_message"` during drain disable.
|
|
|
|
- `-meta <key>=<value>`: Custom metadata to store on the drain operation, can be
|
|
used multiple times.
|
|
|
|
- `-self`: Drain the local node.
|
|
|
|
- `-yes`: Automatic yes to prompts.
|
|
|
|
## Examples
|
|
|
|
Enable drain mode on node with ID prefix "4d2ba53b":
|
|
|
|
```shell-session
|
|
$ nomad node drain -enable f4e8a9e5 -m "node maintenance"
|
|
Are you sure you want to enable drain mode for node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e"? [y/N] y
|
|
2018-03-30T23:13:16Z: Ctrl-C to stop monitoring: will not cancel the node drain
|
|
2018-03-30T23:13:16Z: Node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" drain strategy set
|
|
2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" marked for migration
|
|
2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" draining
|
|
2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" status running -> complete
|
|
2018-03-30T23:13:29Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" marked for migration
|
|
2018-03-30T23:13:29Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" draining
|
|
2018-03-30T23:13:30Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" status running -> complete
|
|
2018-03-30T23:13:41Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" marked for migration
|
|
2018-03-30T23:13:41Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" draining
|
|
2018-03-30T23:13:41Z: Node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" has marked all allocations for migration
|
|
2018-03-30T23:13:42Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" status running -> complete
|
|
2018-03-30T23:13:42Z: All allocations on node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" have stopped.
|
|
```
|
|
|
|
Enable drain mode on the local node:
|
|
|
|
```shell-session
|
|
$ nomad node drain -enable -self
|
|
...
|
|
```
|
|
|
|
Enable drain mode but do not stop system jobs:
|
|
|
|
```shell-session
|
|
$ nomad node drain -enable -ignore-system 4d2ba53b
|
|
...
|
|
```
|
|
|
|
Disable drain mode but keep the node ineligible for scheduling. Useful for
|
|
inspecting the current state of a misbehaving node without Nomad trying to
|
|
start or migrate allocations:
|
|
|
|
```shell-session
|
|
$ nomad node drain -disable -keep-ineligible 4d2ba53b
|
|
...
|
|
```
|
|
|
|
Enable drain mode and detach from monitoring, then reattach later:
|
|
|
|
```shell-session
|
|
$ nomad node drain -enable -detach -self
|
|
...
|
|
$ nomad node drain -self -monitor
|
|
...
|
|
```
|
|
|
|
[eligibility]: /docs/commands/node/eligibility
|
|
[migrate]: /docs/job-specification/migrate
|
|
[node status]: /docs/commands/node/status
|
|
[workload migration guide]: https://learn.hashicorp.com/tutorials/nomad/node-drain
|
|
[internals-csi]: /docs/internals/plugins/csi
|