docker commandline

Posted 2021-06-05 呆雁

https://docs.docker.com/engine/reference/commandline/run/

https://docs.docker.com/engine/reference/commandline/exec/

• docker run – Runs a command in a new container.
• docker start – Starts one or more stopped containers
• docker stop – Stops one or more running containers
• docker build – Builds an image form a Docker file
• docker pull – Pulls an image or a repository from a registry
• docker push – Pushes an image or a repository to a registry
• docker export – Exports a container’s filesystem as a tar archive
• docker exec – Runs a command in a run-time container
• docker search – Searches the Docker Hub for images
• docker attach – Attaches to a running container
• docker commit – Creates a new image from a container’s changes

--ipc=host and --ipc=container:id选项已添加到Docker create和run命令中以共享IPC资源。

--ipc=""  : Set the IPC mode for the container,
             \'container:<name|id>\': reuses another container\'s IPC namespace
             \'host\': use the host\'s IPC namespace inside the container

Configure namespaced kernel parameters (sysctls) at runtime

The --sysctl sets namespaced kernel parameters (sysctls) in the container. For example, to turn on IP forwarding in the containers network namespace, run this command:

$ docker run --sysctl net.ipv4.ip_forward=1 someimage

Note

Not all sysctls are namespaced. Docker does not support changing sysctls inside of a container that also modify the host system. As the kernel evolves we expect to see more sysctls become namespaced.

CURRENTLY SUPPORTED SYSCTLS

IPC Namespace:

• kernel.msgmax, kernel.msgmnb, kernel.msgmni, kernel.sem, kernel.shmall, kernel.shmmax, kernel.shmmni, kernel.shm_rmid_forced.
• Sysctls beginning with fs.mqueue.*
• If you use the --ipc=host option these sysctls are not allowed.

Network Namespace:

• Sysctls beginning with net.*
• If you use the --network=host option using these sysctls are not allowed.

 

System V共享内存(shmget、shmat、shmdt)以及Mmap映射Regular File。System V共享内存支持一定程度上的内存数据持久化，即当程序创建共享内存对象后，如果不显式删除或物理主机重启，该IPC对象会一直保留，其中的数据也不会丢 失；mmap映射Regular File的方式支持内存数据持久化到文件中，即便物理主机重启，这部分数据依旧不会丢失，除非显式删除文件。

mmap常见的有两类共享内存映射方式，一种映射到/dev/zero，另外一种则是映射到 Regular Fiile。前者在程序退出后数据自动释放，后者则保留在映射的文件中。

一个启动的Docker容器就是一个拥有了自己的内核名字空间的进程，其pid、net、ipc、mnt、uts、user等均与其他进程隔离，对于运行于该容器内的程序而言，它仿佛会觉得它独占了一台“主机”。

在docker容器中的centos无法使用gdb调试：在docker run 命令中加上参数--cap-add=SYS_PTRACE

 

docker机器上不能使用date -s修改时间： --cap-add=SYS_TIME