From 78c0d50c9fb236f76924c29b2703a0faf11d9dc3 Mon Sep 17 00:00:00 2001 From: Aaron Lehmann Date: Thu, 20 Oct 2016 12:04:01 -0700 Subject: [PATCH] Add force option to service update Currently, there's no way to restart the tasks of a service without making an actual change to the service. This leads to us giving awkward workarounds as in https://github.com/docker/docker.github.io/pull/178/files, where we tell people to scale a service up and down to restore balance, or make unnecessary changes to trigger a restart. This change adds a --force option to "docker service update", which forces the service to be updated even if no changes require that. Since rolling update parameters are respected, the user can use "docker service --force" to do a rolling restart. For example, the following is supported: docker service update --force --update-parallelism 2 \ --update-delay 5s myservice Since the default value of --update-parallelism is 1, the default behavior is to restart the service one task at a time. Signed-off-by: Aaron Lehmann --- contrib/completion/bash/docker | 1 + contrib/completion/zsh/_docker | 1 + docs/reference/commandline/service_update.md | 20 ++++++++++++++++++++ 3 files changed, 22 insertions(+) diff --git a/contrib/completion/bash/docker b/contrib/completion/bash/docker index 746207e02e..6131ff5267 100644 --- a/contrib/completion/bash/docker +++ b/contrib/completion/bash/docker @@ -2473,6 +2473,7 @@ _docker_service_update() { --constraint --endpoint-mode --env -e + --force --group-add --label -l --limit-cpu diff --git a/contrib/completion/zsh/_docker b/contrib/completion/zsh/_docker index e06082721f..415e731f3b 100644 --- a/contrib/completion/zsh/_docker +++ b/contrib/completion/zsh/_docker @@ -1185,6 +1185,7 @@ __docker_service_subcommand() { "($help)--arg=[Service command args]:arguments: _normal" \ "($help)*--container-label-add=[Add or update container labels]:label: " \ "($help)*--container-label-rm=[Remove a container label by its key]:label: " \ + "($help)--force[Force update]" \ "($help)*--group-rm=[Remove previously added user groups from the container]:group:_groups" \ "($help)--image=[Service image tag]:image:__docker_repositories" \ "($help)--rollback[Rollback to previous specification]" \ diff --git a/docs/reference/commandline/service_update.md b/docs/reference/commandline/service_update.md index abbd14a5ac..90b78a4541 100644 --- a/docs/reference/commandline/service_update.md +++ b/docs/reference/commandline/service_update.md @@ -29,6 +29,7 @@ Options: --endpoint-mode string Endpoint mode (vip or dnsrr) --env-add value Add or update environment variables (default []) --env-rm value Remove an environment variable (default []) + --force Force update even if no changes require it --group-add value Add additional user groups to the container (default []) --group-rm value Remove previously added user groups from the container (default []) --help Print usage @@ -67,6 +68,12 @@ Updates a service as described by the specified parameters. This command has to The parameters are the same as [`docker service create`](service_create.md). Please look at the description there for further information. +Normally, updating a service will only cause the service's tasks to be replaced with new ones if a change to the +service requires recreating the tasks for it to take effect. For example, only changing the +`--update-parallelism` setting will not recreate the tasks, because the individual tasks are not affected by this +setting. However, the `--force` flag will cause the tasks to be recreated anyway. This can be used to perform a +rolling restart without any changes to the service parameters. + ## Examples ### Update a service @@ -75,6 +82,19 @@ for further information. $ docker service update --limit-cpu 2 redis ``` +### Perform a rolling restart with no parameter changes + +```bash +$ docker service update --force --update-parallelism 1 --update-delay 30s redis +``` + +In this example, the `--force` flag causes the service's tasks to be shut down +and replaced with new ones even though none of the other parameters would +normally cause that to happen. The `--update-parallelism 1` setting ensures +that only one task is replaced at a time (this is the default behavior). The +`--update-delay 30s` setting introduces a 30 second delay between tasks, so +that the rolling restart happens gradually. + ### Adding and removing mounts Use the `--mount-add` or `--mount-rm` options add or remove a service's bind-mounts