Docker-2 learn more about docker, docker-2docker
DockerBasic concepts of images, containers, and warehousesImages
- A Docker image is a read-only template.
For example, an image can contain a complete CentOS operating system environment where only httpd or other applications are installed.
- Images can be used to create Docker containers.
- Docker provides a simple mechanism to create an image or update an existing image. Users can even directly download an existing image from others for direct use.
Container
- Docker uses containers to run applications.
- A container is a running instance created from an image. It can be started, started, stopped, or deleted. Each container is an isolated and secure platform.
- Containers can be viewed as a simple Linux environment (including root user permissions, process space, user space and network space) and applications running in it.
- * Note: The image is read-only. when the container is started, a writable layer is created as the top layer.
Warehouse
- A repository Stores image files in a centralized manner. Sometimes the repository and Registry are confused and not strictly differentiated. In fact, the repository registration server often stores multiple repositories, each of which contains multiple images, each of which has different tags ).
- A repository can be either Public or Private.
- The largest public repository is Docker Hub, which stores a large number of images for users to download. As the default docker repository, the download speed in China is very slow. Of course, you can also create a private repository in the local network. After creating your own image, you can use the push command to upload it to a public or private repository, so that the next time you use this image on another machine, you only need to pull the repository.
- * Note: The concept of Docker repository is similar to that of Git. The registration server can be understood as a hosting service such as GitHub.
Docker container installation
RedHat/CentOS must be version 6.6 or later, or 7. x to install docker. We recommend that you use docker on RedHat/CentOS 7 because the kernel of RedHat/CentOS 7 is upgraded to kernel 3.10, which provides better support for lxc containers.
Centos6.6 install docker
rpm -ivh http://mirrors.yun-idc.com/epel/6Server/x86_64/epel-release-6-8.noarch.rpmyum install docker-io chkconfig docker onservice docker startdocker version
Startup Problems
Question: Docker # docker dead but pid file exists
Solution:
yum-config-manager --enable public_ol6_latestyum install device-mapper-event-libs
01:04:10
