# Apply rolling updates to a service In a previous step of the tutorial, you [scaled](scale-service.md) the number of instances of a service. In this part of the tutorial, you deploy a service based on the Redis 3.0.6 container image. Then you upgrade the service to use the Redis 3.0.7 container image using rolling updates. 1. If you haven't already, open a terminal and ssh into the machine where you run your manager node. For example, the tutorial uses a machine named `manager1`. 2. Deploy Redis 3.0.6 to the swarm and configure the swarm to update one node every 10 seconds: ```bash $ docker service create --replicas 3 --name redis --update-delay 10s --update-parallelism 1 redis:3.0.6 0u6a4s31ybk7yw2wyvtikmu50 ``` You configure the rolling update policy at service deployment time. The `--update-parallelism` flag configures the number of service tasks to update simultaneously. The `--update-delay` flag configures the time delay between updates to a 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. 3. Inspect the `redis` service: ```bash $ docker service inspect redis --pretty ID: 0u6a4s31ybk7yw2wyvtikmu50 Name: redis Mode: REPLICATED Replicas: 3 Placement: Strategy: SPREAD UpdateConfig: Parallelism: 1 Delay: 10s ContainerSpec: Image: redis:3.0.6 ``` 4. Now you can update the container image for `redis`. The swarm manager applies the update to nodes according to the `UpdateConfig` policy: ```bash $ docker service update --image redis:3.0.7 redis redis ``` 5. Run `docker service inspect --pretty redis` to see the new image in the desired state: ```bash docker service inspect --pretty redis ID: 0u6a4s31ybk7yw2wyvtikmu50 Name: redis Mode: REPLICATED Replicas: 3 Placement: Strategy: SPREAD UpdateConfig: Parallelism: 1 Delay: 10s ContainerSpec: Image: redis:3.0.7 ``` 6. Run `docker service tasks ` to watch the rolling update: ```bash $ docker service tasks redis ID NAME SERVICE IMAGE LAST STATE DESIRED STATE NODE dos1zffgeofhagnve8w864fco redis.1 redis redis:3.0.7 Running 37 seconds Running worker1 9l3i4j85517skba5o7tn5m8g0 redis.2 redis redis:3.0.7 Running About a minute Running worker2 egiuiqpzrdbxks3wxgn8qib1g redis.3 redis redis:3.0.7 Running 48 seconds Running worker1 ``` Before Swarm updates all of the tasks, you can see that some are running `redis:3.0.6` while others are running `redis:3.0.7`. The output above shows the state once the rolling updates are done. You can see that each instances entered the `RUNNING` state in approximately 10 second increments. Next, learn about how to [drain a node](drain-node.md) in the Swarm.