Docker is an open-source containerization platform to run on Windows, Linux, and macOS.
Are you trying to resolve "Docker: unrecognized service" error ? We can help you.
In this context, we shall look into steps to resolve this docker error.
Nature of "Docker: unrecognized service" error
After installing Docker on Centos, users may see this error while trying to start the Docker service:
# service docker start
docker: unrecognized service
In this guide, you will see different ways to tackle this issue.
Ways to fix "Docker: unrecognized service" error ?
1. Remove docker and then edit Repo
First, remove the docker using below command:
$ yum remove docker
Then remove docker-selinux (if you have installed it before):
$ yum remove docker-selinux
Then modify the file:
$ vi /etc/yum.repos.d/docker.repo
Fill in the following content directly:
Then start the installation:
$ yum install docker-engine
Installed as a dependency: docker-engine-selinux.noarch 0:1.10.2-1.el7.centos
Finally, start the docker service:
$ service docker start
The following status code is returned:
Starting cgconfig service: [OK]
Starting docker: [OK]
This ensures that the docker starts successfully.
2. Re-install docker
Here, you can directly install using below command:
# curl -fsSL https://get.docker.com/ | sh + sh -c’sleep 3; yum -y -q install docker-engine’
You might see the below prompt message which can be ignored:
Warning: /var/cache/yum/x86_64/7/docker-main-repo/packages/docker-engine-selinux-1.10.2-1.el7.centos.noarch.rpm: header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY docker-engine-selinux-1.10.2-1.el7.centos.noarch.rpm public key has not been installed Import GPG key 0x2C52609D: User ID: “Docker Release Tool (releasedocker) “Fingerprint: 5811 8e89 f3a9 1289 7c07 0adb f762 2157 2c52 609d From: https://yum.dockerproject.org/gpg setsebool: SELinux is disabled. + sh -c’docker version’ Client: Version: 1.10.2 API version: 1.22 Go version: go1.5.3 Git commit: c3959b1 Built: Mon Feb 22 16:16:33 2016 OS/Arch: linux/amd64 Cannot connect to the Docker daemon. Is the docker daemon running on this host? If you would like to use Docker as a non-root user, you should now consider adding your user to the “docker” group with something like: sudo usermod -aG docker your-user Remember that you will have to log out and back in for this to take effect!
Then just start it directly using the below command:
$ service docker start Redirecting to /bin/systemctl start docker.service