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105 lines
3.2 KiB
Markdown
105 lines
3.2 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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[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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advisory = "rc"
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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 new Redis
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service and upgrade the service 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 all nodes in the Swarm and configure
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the swarm to update one node every 10 seconds:
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```bash
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$ docker service create --scale 3 --name redis --update-delay 10s --update-parallelism 1 redis:3.0.6
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8m228injfrhdym2zvzhl9k3l0
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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
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a service task or sets of tasks. You can describe the time `T` in the number
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of seconds `Ts`, minutes `Tm`, or hours `Th`. So `10m` indicates a 10 minute
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delay.
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3. Inspect the `redis` service:
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```
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$ docker service inspect redis --pretty
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ID: 75kcmhuf8mif4a07738wttmgl
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Name: redis
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Mode: REPLICATED
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Scale: 3
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Placement:
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Strategy: SPREAD
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UpateConfig:
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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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```
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4. Now you can update the container image for `redis`. Swarm applies the update
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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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```
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docker service inspect --pretty redis
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ID: 1yrcci9v8zj6cokua2eishlob
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Name: redis
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Mode: REPLICATED
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Scale: 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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```
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6. Run `docker service tasks TASK-ID` to watch the rolling update:
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```
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$ docker service tasks redis
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ID NAME SERVICE IMAGE DESIRED STATE LAST STATE NODE
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5409nu4crb0smamziqwuug67u redis.1 redis redis:3.0.7 RUNNING RUNNING 21 seconds worker2
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b8ezq58zugcg1trk8k7jrq9ym redis.2 redis redis:3.0.7 RUNNING RUNNING 1 seconds worker1
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cgdcbipxnzx0y841vysiafb64 redis.3 redis redis:3.0.7 RUNNING RUNNING 11 seconds 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 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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<p style="margin-bottom:300px"> </p>
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