github.com/brahmaroutu/docker@v1.2.1-0.20160809185609-eb28dde01f16/docs/reference/commandline/update.md (about)

     1  <!--[metadata]>
     2  +++
     3  title = "update"
     4  description = "The update command description and usage"
     5  keywords = ["resources, update, dynamically"]
     6  [menu.main]
     7  parent = "smn_cli"
     8  +++
     9  <![end-metadata]-->
    10  
    11  ## update
    12  
    13  ```markdown
    14  Usage:  docker update [OPTIONS] CONTAINER [CONTAINER...]
    15  
    16  Update configuration of one or more containers
    17  
    18  Options:
    19        --blkio-weight value          Block IO (relative weight), between 10 and 1000
    20        --cpu-period int              Limit CPU CFS (Completely Fair Scheduler) period
    21        --cpu-quota int               Limit CPU CFS (Completely Fair Scheduler) quota
    22    -c, --cpu-shares int              CPU shares (relative weight)
    23        --cpuset-cpus string          CPUs in which to allow execution (0-3, 0,1)
    24        --cpuset-mems string          MEMs in which to allow execution (0-3, 0,1)
    25        --help                        Print usage
    26        --kernel-memory string        Kernel memory limit
    27    -m, --memory string               Memory limit
    28        --memory-reservation string   Memory soft limit
    29        --memory-swap string          Swap limit equal to memory plus swap: '-1' to enable unlimited swap
    30        --restart string              Restart policy to apply when a container exits
    31  ```
    32  
    33  The `docker update` command dynamically updates container configuration.
    34  You can use this command to prevent containers from consuming too many 
    35  resources from their Docker host.  With a single command, you can place 
    36  limits on a single container or on many. To specify more than one container,
    37  provide space-separated list of container names or IDs.
    38  
    39  With the exception of the `--kernel-memory` option, you can specify these
    40  options on a running or a stopped container. On kernel version older than
    41  4.6, you can only update `--kernel-memory` on a stopped container or on
    42  a running container with kernel memory initialized.
    43  
    44  ## EXAMPLES
    45  
    46  The following sections illustrate ways to use this command.
    47  
    48  ### Update a container's cpu-shares
    49  
    50  To limit a container's cpu-shares to 512, first identify the container
    51  name or ID. You can use `docker ps` to find these values. You can also
    52  use the ID returned from the `docker run` command.  Then, do the following:
    53  
    54  ```bash
    55  $ docker update --cpu-shares 512 abebf7571666
    56  ```
    57  
    58  ### Update a container with cpu-shares and memory
    59  
    60  To update multiple resource configurations for multiple containers:
    61  
    62  ```bash
    63  $ docker update --cpu-shares 512 -m 300M abebf7571666 hopeful_morse
    64  ```
    65  
    66  ### Update a container's kernel memory constraints
    67  
    68  You can update a container's kernel memory limit using the `--kernel-memory`
    69  option. On kernel version older than 4.6, this option can be updated on a
    70  running container only if the container was started with `--kernel-memory`.
    71  If the container was started *without* `--kernel-memory` you need to stop
    72  the container before updating kernel memory.
    73  
    74  For example, if you started a container with this command:
    75  
    76  ```bash
    77  $ docker run -dit --name test --kernel-memory 50M ubuntu bash
    78  ```
    79  
    80  You can update kernel memory while the container is running:
    81  
    82  ```bash
    83  $ docker update --kernel-memory 80M test
    84  ```
    85  
    86  If you started a container *without* kernel memory initialized:
    87  
    88  ```bash
    89  $ docker run -dit --name test2 --memory 300M ubuntu bash
    90  ```
    91  
    92  Update kernel memory of running container `test2` will fail. You need to stop
    93  the container before updating the `--kernel-memory` setting. The next time you
    94  start it, the container uses the new value.
    95  
    96  Kernel version newer than (include) 4.6 does not have this limitation, you
    97  can use `--kernel-memory` the same way as other options.
    98  
    99  ### Update a container's restart policy
   100  
   101  You can change a container's restart policy on a running container. The new
   102  restart policy takes effect instantly after you run `docker update` on a
   103  container.
   104  
   105  To update restart policy for one or more containers:
   106  
   107  ```bash
   108  $ docker update --restart=on-failure:3 abebf7571666 hopeful_morse
   109  ```