What is an unprivileged LXC container?

Published by Anaya Cole on

What is an unprivileged LXC container?

Unprivileged LXC containers are the ones making use of user namespaces (userns). I.e. of a kernel feature that allows to map a range of UIDs on the host into a namespace inside of which a user with UID 0 can exist again.

Does LXC require root?

LXC upstream’s position is that those containers aren’t and cannot be root-safe. They are still valuable in an environment where you are running trusted workloads or where no untrusted task is running as root in the container.

How do I know if my LXC container is privileged?

If it’s a LXD container, look for “security. privileged: true” in “lxc config show –expanded NAME”. If it’s there, it’s a privileged container, if it’s not, it’s an unprivileged container. For LXC, you can check for lxc.

Does Docker use LXC?

Docker is developed in the Go language and utilizes LXC, cgroups, and the Linux kernel itself. Since it’s based on LXC, a Docker container does not include a separate operating system; instead it relies on the operating system’s own functionality as provided by the underlying infrastructure.

Where does LXC storage containers?

By default, containers are located under /var/lib/lxc for the root user.

What is the difference between LXC and LXD?

LXD is an open source container management extension for Linux Containers (LXC). LXD both improves upon existing LXC features and provides new features and functionality to build and manage Linux containers.

What is the difference between Lxc and LXD?

Does Docker use LXD?

Running Docker in LXD You can use LXD to create your virtual systems running inside the containers, segment them as you like, and easily use Docker to get the actual service running inside of the container.

What is the difference between lxc and LXD?

What is the difference between LXC and Docker?

LXC focuses on OS containerization, while Docker thrives on application containerization. Docker is single-purpose application virtualization, and LXC is multi-purpose operating system virtualization. In this case, LXC specializes in deploying Linux Virtual machines.

How does LXC work with unprivileged containers?

To make unprivileged containers work, LXC interacts with 3 pieces of setuid code: lxc-user-nic (setuid helper to create a veth pair and bridge it on the host) newuidmap (from the shadow package, sets up a uid map) newgidmap (from the shadow package, sets up a gid map)

Why are unprivileged users not allowed in containers?

This means that most security issues (container escape, resource abuse, …) in those containers will affect a random unprivileged user, even if the container itself would do it as root user, and so would be a generic kernel security bug rather than an LXC issue. The LXC team thinks unprivileged containers are safe by design.

How many LXC bridges should be created for a container?

When running untrusted containers or when allowing untrusted users to run containers, one should ideally create one bridge per user or per group of untrusted containers and configure /etc/lxc/lxc-usernet such that users may only use the bridges that they have been allocated.

How to start a LXC container with a shared UID?

You can start or restart the container here, it should start and see /shared mapped from the host directory /mnt/bindmounts/shared, all uids will be mapped to 65534:65534 except 1005, which would be seen (and written) as 1005:1005. In case of problems debugging could be done by lxc-start -F -n 1234 .

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