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477a5f8fb0
The output uses tabs, but those don't translate well to the rendered output in the docs, so replacing the tabs with spaces. Also updates the output, because REPLICATED, and SPREAD are no longer all-caps in the actual output. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
111 lines
3.5 KiB
Markdown
111 lines
3.5 KiB
Markdown
<!--[metadata]>
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+++
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title = "Apply rolling updates"
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description = "Apply rolling updates to a service on the Swarm"
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keywords = ["tutorial, cluster management, swarm, service, rolling-update"]
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advisory = "rc"
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[menu.main]
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identifier="swarm-tutorial-rolling-update"
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parent="swarm-tutorial"
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weight=20
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+++
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<![end-metadata]-->
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# Apply rolling updates to a service
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In a previous step of the tutorial, you [scaled](scale-service.md) the number of
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instances of a service. In this part of the tutorial, you deploy a service based
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on the Redis 3.0.6 container image. Then you upgrade the service to use the
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Redis 3.0.7 container image using rolling updates.
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1. If you haven't already, open a terminal and ssh into the machine where you
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run your manager node. For example, the tutorial uses a machine named
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`manager1`.
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2. Deploy Redis 3.0.6 to the swarm and configure the swarm to update one node
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every 10 seconds:
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```bash
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$ docker service create --replicas 3 --name redis --update-delay 10s --update-parallelism 1 redis:3.0.6
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0u6a4s31ybk7yw2wyvtikmu50
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```
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You configure the rolling update policy at service deployment time.
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The `--update-parallelism` flag configures the number of service tasks
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to update simultaneously.
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The `--update-delay` flag configures the time delay between updates to a
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service task or sets of tasks. You can describe the time `T` as a
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combination of the number of seconds `Ts`, minutes `Tm`, or hours `Th`. So
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`10m30s` indicates a 10 minute 30 second delay.
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3. Inspect the `redis` service:
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```bash
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$ docker service inspect redis --pretty
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ID: 0u6a4s31ybk7yw2wyvtikmu50
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Name: redis
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Mode: Replicated
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Replicas: 3
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Placement:
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Strategy: Spread
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UpdateConfig:
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Parallelism: 1
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Delay: 10s
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ContainerSpec:
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Image: redis:3.0.6
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Resources:
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Reservations:
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Limits:
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```
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4. Now you can update the container image for `redis`. The swarm manager
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applies the update to nodes according to the `UpdateConfig` policy:
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```bash
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$ docker service update --image redis:3.0.7 redis
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redis
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```
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5. Run `docker service inspect --pretty redis` to see the new image in the
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desired state:
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```bash
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$ docker service inspect --pretty redis
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ID: 0u6a4s31ybk7yw2wyvtikmu50
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Name: redis
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Mode: Replicated
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Replicas: 3
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Placement:
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Strategy: Spread
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UpdateConfig:
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Parallelism: 1
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Delay: 10s
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ContainerSpec:
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Image: redis:3.0.7
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Resources:
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Reservations:
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Limits:
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```
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6. Run `docker service tasks <TASK-ID>` to watch the rolling update:
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```bash
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$ docker service tasks redis
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ID NAME SERVICE IMAGE LAST STATE DESIRED STATE NODE
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dos1zffgeofhagnve8w864fco redis.1 redis redis:3.0.7 Running 37 seconds Running worker1
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9l3i4j85517skba5o7tn5m8g0 redis.2 redis redis:3.0.7 Running About a minute Running worker2
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egiuiqpzrdbxks3wxgn8qib1g redis.3 redis redis:3.0.7 Running 48 seconds Running worker1
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```
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Before Swarm updates all of the tasks, you can see that some are running
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`redis:3.0.6` while others are running `redis:3.0.7`. The output above shows
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the state once the rolling updates are done. You can see that each instances
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entered the `RUNNING` state in approximately 10 second increments.
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Next, learn about how to [drain a node](drain-node.md) in the Swarm.
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