Rootless Containers
[Optional] sysctl
Note
Configuring sysctl is optional for most distributions.
Old versions of Debian, Arch, and RHEL/CentOS are known to require reconfiguration of sysctl to enable User Namespaces.
Note
These steps are not needed for Debian 11. These steps are also not needed for Ubuntu.
Create /etc/sysctl.d/99-rootless.conf with the following content:
kernel.unprivileged_userns_clone=1
Then run the following command to reload the new sysctl configuration:
$ sudo sysctl --system
Note
These steps are no longer needed for Arch Linux as of April 2021.
Create /etc/sysctl.d/99-rootless.conf with the following content:
kernel.unprivileged_userns_clone=1
Then run the following command to reload the new sysctl configuration:
sudo sysctl --system
Note
These steps are not needed for RHEL/CentOS 8.
Create /etc/sysctl.d/99-rootless.conf with the following content:
user.max_user_namespaces=28633
Then run the following command to reload the new sysctl configuration:
sudo sysctl --system
Most distributions do not allow non-root users to send ICMP Echo Request packets (aka ping) by default.
To allow running ping without root, create /etc/sysctl.d/99-rootless.conf with the following content:
net.ipv4.ping_group_range = 0 2147483647
Then run the following command to reload the new sysctl configuration:
sudo sysctl --system
Most distributions do not allow non-root users to listen on TCP & UDP ports below 1024. e.g. listening on 80/tcp would fail with “permission denied”, while listening on 8080/tcp would success.
To allow listening on any port without root, create /etc/sysctl.d/99-rootless.conf with the following content:
net.ipv4.ip_unprivileged_port_start=0
Then run the following command to reload the new sysctl configuration:
sudo sysctl --system