jaebill.blogg.se - Docker run as root in container

$ docker exec bash -c "command1 command2 command3" In order to execute multiple commands using the “docker exec” command, execute “docker exec” with the “bash” process and use the “-c” option to read the command as a string. Great, you are now able to run commands as the root user within a container with docker exec. $ docker exec -u 0 įor example, in order to make sure that we execute the command as root, let’s have a command that prints the user currently logged in the container. In order to execute a command as root on a container, use the “docker exec” command and specify the “-u” with a value of 0 for the root user. In some cases, you are interested in running commands in your container as the root user. If you don’t specify the “IT” option, Bash will still get executed in the container but you won’t be able to submit commands to it. In order to get the results from your command, you are also binding the standard output and the standard error to the ones from your host machine.Īs you are binding the standard input from your host to the standard input of your container, you are running the command “interactively”. When running “ docker exec” with the “-i” option, you are binding the standard input of your host to the standard input of the process you are running in the container. So how are file descriptors related to the “ docker exec“?

STDERR : called the standard error, it is very related to the standard output and is used in order to display errors.

STDOUT : called the standard output, this is where the process outputs will be written (the terminal itself, a file, a database etc.).

STDIN : also called the standard input that will be used in order to type and submit your commands (for example a keyboard, a terminal etc.).

Whenever you are executing a command, you are creating three file descriptors : If you are familiar with Linux operating systems, you have probably already heard about the concept of file descriptors. What is the purpose of those options? Docker Exec Interactive Option (IT) When executing this command, you will have an interactive Bash terminal where you can execute all the commands that you want.Īwesome, you are now running an interactive Bash terminal within your container.Īs you can see, we used an option that we did not use before to execute our command : the I and T options. If the Bash is part of your PATH, you can simply type “bash” and have a Bash terminal in your container. In order to start a Bash shell in a Docker container, execute the “docker exec” command with the “-it” option and specify the container ID as well as the path to the bash shell. The most popular usage of the “ docker exec” command is to launch a Bash terminal within a container. $ docker exec 74f86665f0fd lsĪwesome, now that you know how you can use the “ docker exec” command, let’s see some custom examples on usage of this command. Now, to execute the “ls” command on this container, simply append the ‘ls’ command to the ID of your container.

Note : the “docker ps” is also used in order to determine whether a container is running or not.Īs you can see, the container ID is the first column of the ‘docker ps’ output. $ docker psĬONTAINER ID IMAGE COMMAND CREATED STATUSħ4f86665f0fd ubuntu:18.04 "/bin/bash" 49 seconds ago Up 48 seconds

In order to determine the container name or ID, you can simply execute the “docker ps” command. The first thing that you need to do is to identify the container name (if you gave your container one) or the container ID. $ docker exec Īs an example, let’s say that you want to execute the “ls” command on one of your containers. In order to execute commands on running containers, you have to execute “docker exec” and specify the container name (or ID) as well as the command to be executed on this container. Executing a command in a specific directory.