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howtos:misc:lxc [2018/09/15 04:40 (UTC)]
montagdude Add some more sections |
howtos:misc:lxc [2018/09/15 20:57 (UTC)]
montagdude [Sharing Directories with the Host] Clarify that lxcpath is a variable |
| ===== Introduction ===== | ===== Introduction ===== |
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| Linux Containers, or LXC, is operating system-level method for running multiple separate isolated Linux installations (containers) on a single host. Rather than simulating the computer hardware as in true virtualization, LXC uses the cgroups and namespaces functionality of the host's Linux kernel to provide strong isolation of the container. It is an intermediate solution between chroots and full virtualization, having a small impact on system resource usage similar to chroots, but providing better isolation. They provide a very convenient way to, among other things, maintain a clean build environment or test software against different [Linux] OS versions. | Linux Containers, or LXC, is operating system-level method for running multiple separate isolated Linux installations (containers) on a single host. Rather than simulating the computer hardware as in true virtualization, LXC uses the cgroups and namespaces functionalities of the host's Linux kernel to provide strong isolation of the container. It is an intermediate solution between chroots and full virtualization, having a small impact on system resource usage similar to chroots, but providing better isolation. It provides a very convenient way to, among other things, maintain a clean build environment or test software against different [Linux] OS versions. |
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| ===== Setting up a Network Bridge ===== | ===== Setting up a Network Bridge ===== |
| </code> | </code> |
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| The name of the bridge, gateway, netmask, and many other parameters can be modified in /etc/default/lxc/lxc-net. For a complete list, simply open up /usr/libexec/lxc/lxc-net in your favorite editor or pager; there is a comment indicating which variables can be changed. | The name of the bridge, gateway, netmask, and many other parameters can be modified by setting the proper variables in /etc/default/lxc/lxc-net. For a complete list, simply open up /usr/libexec/lxc/lxc-net in your favorite editor or pager; there is a comment indicating which variables can be changed. Set them in /etc/default/lxc/lxc-net rather than modifying /usr/libexec/lxc/lxc-net directly. |
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| To actually use this network within the container, there are a few steps that will need to be taken during the initial creation and setup of the container, which will be covered in the next section. | To actually use this network within the container, there are a few steps that will need to be taken during the initial creation and setup of the container, which will be covered in the next section. |
| </code> | </code> |
| |
| When lxc-create is executed, the container will be created at lxcpath/container_name, and slackpkg will download and install the packages needed for a minimal install. The mirror will also be appended to /etc/slackpkg/mirrors. | When lxc-create is executed, the container will be created at $lxcpath/container_name, and slackpkg will download and install the packages needed for a minimal install. The mirror will also be appended to /etc/slackpkg/mirrors. |
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| ===== Container Configuration ===== | ===== Container Configuration ===== |
| |
| <note tip> | <note tip> |
| The minimal Slackware installation set up by lxc-create does not have a lot of choice in editors, but //vi// (symlink to //elvis//) is available. If that's not your cup of tea, you can always edit the container's config files from the host using whichever editor you prefer. The container's entire filesystem is at lxcpath/container_name/rootfs. | The minimal Slackware installation set up by lxc-create does not have a lot of choice in editors, but //vi// (symlink to //elvis//) is available. If that's not your cup of tea, you can always edit the container's config files from the host using whichever editor you prefer. The container's entire filesystem is at $lxcpath/container_name/rootfs. |
| </note> | </note> |
| |
| ==== Sharing Directories with the Host ==== | ==== Sharing Directories with the Host ==== |
| |
| Because an LXC container's filesystem is just a directory on the host, if you only need to transfer files from the host to the container, you can simply copy them over. However, often you will want to share the files both ways, or rather, be able to access //the same files// within the container without having to actually transfer anything, and this is a little more difficult because the container is isolated. LXC provides utilities to mount host directories on containers for this purpose. We will assume that the directory to be shared is at /home/username/foo on the host. To share a user directory with the host, first log into the container and create the top-level of the directory to be shared. Then log out and stop the container. Add the following lines to the container's config file (lxcpath/container_name/config): | Because an LXC container's filesystem is just a directory on the host, if you only need to transfer files from the host to the container, you can simply copy them over. However, often you will want to share the files both ways, or rather, be able to access //the same files// within the container without having to actually transfer anything, and this is a little more difficult due to the isolation of the container. LXC provides utilities to mount host directories on containers for this purpose. We will assume that the directory to be shared is at /home/username/foo on the host. To share a user directory with the host, first log into the container and create the top-level of the directory to be shared. Then log out and stop the container. Add the following lines to the container's config file ($lxcpath/container_name/config): |
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| <code> | <code> |
