path: root/devdocs/docker/engine%2Fswarm%2Fswarm-tutorial%2Fscale-service%2Findex.html

<h1>Scale the service in the swarm</h1>
<p>Once you have <a href="../deploy-service/index">deployed a service</a> to a swarm, you are ready to use the Docker CLI to scale the number of containers in the service. Containers running in a service are called “tasks.”</p> <ol> <li> <p>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 <code class="language-plaintext highlighter-rouge">manager1</code>.</p> </li> <li> <p>Run the following command to change the desired state of the service running in the swarm:</p> <div class="highlight"><pre class="highlight" data-language="">$ docker service scale &lt;SERVICE-ID&gt;=&lt;NUMBER-OF-TASKS&gt;
</pre></div>  <p>For example:</p> <div class="highlight"><pre class="highlight" data-language="">$ docker service scale helloworld=5

helloworld scaled to 5
</pre></div>  </li> <li> <p>Run <code class="language-plaintext highlighter-rouge">docker service ps &lt;SERVICE-ID&gt;</code> to see the updated task list:</p> <div class="highlight"><pre class="highlight" data-language="">$ docker service ps helloworld

NAME                                    IMAGE   NODE      DESIRED STATE  CURRENT STATE
helloworld.1.8p1vev3fq5zm0mi8g0as41w35  alpine  worker2   Running        Running 7 minutes
helloworld.2.c7a7tcdq5s0uk3qr88mf8xco6  alpine  worker1   Running        Running 24 seconds
helloworld.3.6crl09vdcalvtfehfh69ogfb1  alpine  worker1   Running        Running 24 seconds
helloworld.4.auky6trawmdlcne8ad8phb0f1  alpine  manager1  Running        Running 24 seconds
helloworld.5.ba19kca06l18zujfwxyc5lkyn  alpine  worker2   Running        Running 24 seconds
</pre></div>  <p>You can see that swarm has created 4 new tasks to scale to a total of 5 running instances of Alpine Linux. The tasks are distributed between the three nodes of the swarm. One is running on <code class="language-plaintext highlighter-rouge">manager1</code>.</p> </li> <li> <p>Run <code class="language-plaintext highlighter-rouge">docker ps</code> to see the containers running on the node where you’re connected. The following example shows the tasks running on <code class="language-plaintext highlighter-rouge">manager1</code>:</p> <div class="highlight"><pre class="highlight" data-language="">$ docker ps

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
528d68040f95        alpine:latest       "ping docker.com"   About a minute ago   Up About a minute                       helloworld.4.auky6trawmdlcne8ad8phb0f1
</pre></div>  <p>If you want to see the containers running on other nodes, ssh into those nodes and run the <code class="language-plaintext highlighter-rouge">docker ps</code> command.</p> </li> </ol> <h2 id="whats-next">What’s next?</h2> <p>At this point in the tutorial, you’re finished with the <code class="language-plaintext highlighter-rouge">helloworld</code> service. The next step shows how to <a href="../delete-service/index">delete the service</a>.</p> 
<p><a href="https://docs.docker.com/search/?q=tutorial">tutorial</a>, <a href="https://docs.docker.com/search/?q=cluster%20management">cluster management</a>, <a href="https://docs.docker.com/search/?q=swarm%20mode">swarm mode</a>, <a href="https://docs.docker.com/search/?q=scale">scale</a></p>
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