title: Alpine: Wait for docker to start before continue
body: <p>I am using Alpine linux for my CI/CD machine. The docker file below: </p>
  
  <pre><code>FROM node:10.15-alpine
  RUN npm i -g sequelize sequelize-cli mysql2
  RUN echo "http://dl-cdn.alpinelinux.org/alpine/edge/testing" &gt;&gt; /etc/apk/repositories
  RUN apk update
  RUN apk add --update git bash openssh terraform aws-cli docker openrc
  WORKDIR /var/app
  </code></pre>
  
  <p>Problem is when the CI tries to execute docker code, eg. <code>docker login</code>, it fails: </p>
  
  <pre><code>[Container] 2019/01/10 11:18:10 Running command $(aws ecr get-login --region $AWS_DEFAULT_REGION --no-include-email)
  WARNING! Using --password via the CLI is insecure. Use --password-stdin.
  Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?). Using system default: https://index.docker.io/v1/
  Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
   [Container] 2019/01/10 11:18:10 Command did not exit successfully $(aws ecr get-login --region $AWS_DEFAULT_REGION --no-include-email) exit status 1
  </code></pre>
  
  <p>When I try to add the line </p>
  
  <pre><code>RUN service docker start
  </code></pre>
  
  <p>I get docker already starting </p>
  
  <p>How can I wait for docker to start then? </p>