github.com/iqoqo/nomad@v0.11.3-0.20200911112621-d7021c74d101/website/pages/docs/commands/node/drain.mdx (about)

     1  ---
     2  layout: docs
     3  page_title: 'Commands: node drain'
     4  sidebar_title: drain
     5  description: |
     6    The node drain command is used to configure a node's drain strategy.
     7  ---
     8  
     9  # Command: node drain
    10  
    11  The `node drain` command is used to toggle drain mode on a given node. Drain
    12  mode prevents any new tasks from being allocated to the node, and begins
    13  migrating all existing allocations away. Allocations will be migrated according
    14  to their [`migrate`][migrate] stanza until the drain's deadline is reached.
    15  
    16  By default the `node drain` command blocks until a node is done draining and
    17  all allocations have terminated. Canceling the `node drain` command _will not_
    18  cancel the drain. Drains may be canceled by using the `-disable` parameter
    19  below.
    20  
    21  When draining more than one node at a time, it is recommended you first disable
    22  [scheduling eligibility][eligibility] on all nodes that will be drained. For
    23  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
    24  placed on another node about to be drained.
    25  
    26  The [node status] command compliments this nicely by providing the current drain
    27  status of a given node.
    28  
    29  See the [Workload Migration guide] for detailed examples of node draining.
    30  
    31  ## Usage
    32  
    33  ```plaintext
    34  nomad node drain [options] <node>
    35  ```
    36  
    37  A `-self` flag can be used to drain the local node. If this is not supplied, a
    38  node ID or prefix must be provided. If there is an exact match, the drain mode
    39  will be adjusted for that node. Otherwise, a list of matching nodes and
    40  information will be displayed.
    41  
    42  It is also required to pass one of `-enable` or `-disable`, depending on which
    43  operation is desired.
    44  
    45  ## General Options
    46  
    47  @include 'general_options.mdx'
    48  
    49  ## Drain Options
    50  
    51  - `-enable`: Enable node drain mode.
    52  
    53  - `-disable`: Disable node drain mode.
    54  
    55  - `-deadline`: Set the deadline by which all allocations must be moved off the
    56    node. Remaining allocations after the deadline are force removed from the
    57    node. Defaults to 1 hour.
    58  
    59  - `-detach`: Return immediately instead of entering monitor mode.
    60  
    61  - `-monitor`: Enter monitor mode directly without modifying the drain status.
    62  
    63  - `-force`: Force remove allocations off the node immediately.
    64  
    65  - `-no-deadline`: No deadline allows the allocations to drain off the node
    66    without being force stopped after a certain deadline.
    67  
    68  - `-ignore-system`: Ignore system allows the drain to complete without stopping
    69    system job allocations. By default system jobs are stopped last.
    70  
    71  - `-keep-ineligible`: Keep ineligible will maintain the node's scheduling
    72    ineligibility even if the drain is being disabled. This is useful when an
    73    existing drain is being cancelled but additional scheduling on the node is not
    74    desired.
    75  
    76  - `-self`: Drain the local node.
    77  
    78  - `-yes`: Automatic yes to prompts.
    79  
    80  ## Examples
    81  
    82  Enable drain mode on node with ID prefix "4d2ba53b":
    83  
    84  ```shell-sessionnomad node drain -enable f4e8a9e5
    85  Are you sure you want to enable drain mode for node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e"? [y/N] y
    86  2018-03-30T23:13:16Z: Ctrl-C to stop monitoring: will not cancel the node drain
    87  2018-03-30T23:13:16Z: Node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" drain strategy set
    88  2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" marked for migration
    89  2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" draining
    90  2018-03-30T23:13:17Z: Alloc "1877230b-64d3-a7dd-9c31-dc5ad3c93e9a" status running -> complete
    91  2018-03-30T23:13:29Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" marked for migration
    92  2018-03-30T23:13:29Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" draining
    93  2018-03-30T23:13:30Z: Alloc "3fce5308-818c-369e-0bb7-f61f0a1be9ed" status running -> complete
    94  2018-03-30T23:13:41Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" marked for migration
    95  2018-03-30T23:13:41Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" draining
    96  2018-03-30T23:13:41Z: Node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" has marked all allocations for migration
    97  2018-03-30T23:13:42Z: Alloc "9a98c5aa-a719-2f34-ecfc-0e6268b5d537" status running -> complete
    98  2018-03-30T23:13:42Z: All allocations on node "f4e8a9e5-30d8-3536-1e6f-cda5c869c35e" have stopped.
    99  ```
   100  
   101  Enable drain mode on the local node:
   102  
   103  ```shell-sessionnomad node drain -enable -self
   104  ...
   105  ```
   106  
   107  Enable drain mode but do not stop system jobs:
   108  
   109  ```shell-sessionnomad node drain -enable -ignore-system 4d2ba53b
   110  ...
   111  ```
   112  
   113  Disable drain mode but keep the node ineligible for scheduling. Useful for
   114  inspecting the current state of a misbehaving node without Nomad trying to
   115  start or migrate allocations:
   116  
   117  ```shell-sessionnomad node drain -disable -keep-ineligible 4d2ba53b
   118  ...
   119  ```
   120  
   121  Enable drain mode and detach from monitoring, then reattach later:
   122  
   123  ```shell-sessionnomad node drain -enable -detach -self
   124  ...
   125  $ nomad node drain -self -monitor
   126  ...
   127  ```
   128  
   129  [eligibility]: /docs/commands/node/eligibility
   130  [migrate]: /docs/job-specification/migrate
   131  [node status]: /docs/commands/node/status
   132  [workload migration guide]: https://learn.hashicorp.com/nomad/operating-nomad/node-draining