From 6440cacd49226e97b2dcb64eb31cb32b87b1ff18 Mon Sep 17 00:00:00 2001
From: Charles Smith <charles.smith@docker.com>
Date: Mon, 25 Jul 2016 09:04:15 -0700
Subject: [PATCH] update rolling update tutorial to reflect default parallelism
and update on failure
Signed-off-by: Charles Smith <charles.smith@docker.com>
---
docs/swarm/swarm-tutorial/rolling-update.md | 62 +++++++++++++++------
1 file changed, 45 insertions(+), 17 deletions(-)
diff --git a/docs/swarm/swarm-tutorial/rolling-update.md b/docs/swarm/swarm-tutorial/rolling-update.md
index 66a15b23b2..141087e531 100644
--- a/docs/swarm/swarm-tutorial/rolling-update.md
+++ b/docs/swarm/swarm-tutorial/rolling-update.md
@@ -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