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update rolling update tutorial to reflect default parallelism and update on failure

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Signed-off-by: Charles Smith <charles.smith@docker.com>
This commit is contained in:
Charles Smith 2016-07-25 09:04:15 -07:00
parent abf0e9f071
commit 6440cacd49
1 changed files with 45 additions and 17 deletions
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62
docs/swarm/swarm-tutorial/rolling-update.md
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@ -29,7 +29,6 @@ update delay:
--replicas 3 \
--name redis \
--update-delay 10s \
--update-parallelism 1 \
redis:3.0.6
0u6a4s31ybk7yw2wyvtikmu50
@ -37,18 +36,21 @@ update delay:
You configure the rolling update policy at service deployment time.
The `--update-parallelism` flag configures the number of service tasks that
the scheduler can update simultaneously. When updates to individual tasks
return a state of `RUNNING` or `FAILED`, the scheduler schedules another
task to update until all tasks are updated.
The `--update-delay` flag configures the time delay between updates to a
service task or sets of tasks.
service task or sets of tasks. You can describe the time `T` as a
combination of the number of seconds `Ts`, minutes `Tm`, or hours `Th`. So
`10m30s` indicates a 10 minute 30 second delay.
You can describe the time `T` as a combination of the number of seconds
`Ts`, minutes `Tm`, or hours `Th`. So `10m30s` indicates a 10 minute 30
second delay.
By default the scheduler updates 1 task at a time. You can pass the
`--update-parallelism` flag to configure the maximum number of service tasks
that the scheduler updates simultaneously.
By default, when an update to an individual task returns a state of
`RUNNING`, the scheduler schedules another task to update until all tasks
are updated. If, at any time during an update a task returns `FAILED`, the
scheduler pauses the update. You can control the behavior using the
`--update-failure-action` flag for `docker service create` or
`docker service update`.
3. Inspect the `redis` service:
@ -77,13 +79,15 @@ applies the update to nodes according to the `UpdateConfig` policy:
redis
```
The scheduler applies rolling updates as follows:
The scheduler applies rolling updates as follows by default:
* Stop the initial number of tasks according to `--update-parallelism`.
* Schedule updates for the stopped tasks.
* Start the containers for the updated tasks.
* After an update to a task completes, wait for the specified delay
period before stopping the next task.
* Stop the first task.
* Schedule update for the stopped task.
* Start the container for the updated task.
* If the update to a task returns `RUNNING`, wait for the
specified delay period then stop the next task.
* If, at any time during the update, a task returns `FAILED`, pause the
update.
5. Run `docker service inspect --pretty redis` to see the new image in the
desired state:
@ -105,7 +109,31 @@ desired state:
Resources:
```
6. Run `docker service tasks <TASK-ID>` to watch the rolling update:
The output of `service inspect` shows if your update paused due to failure:
```bash
$ docker service inspect --pretty redis
ID: 0u6a4s31ybk7yw2wyvtikmu50
Name: redis
...snip...
Update status:
State: paused
Started: 11 seconds ago
Message: update paused due to failure or early termination of task 9p7ith557h8ndf0ui9s0q951b
...snip...
```
To restart a paused update run `docker service update <SERVICE-ID>`. For example:
```bash
docker service update redis
```
To avoid repeating certain update failures, you may need to reconfigure the
service by passing flags to `docker service update`.
6. Run `docker service tasks <SERVICE-ID>` to watch the rolling update:
```bash
$ docker service tasks redis