Installing and configuring an unprivileged lxc container with uid/gid offset.

LANG=C SUITE=bookworm MIRROR=https://ftp.debian.org/debian/ lxc-create --name=unprivileged-lxc --template=debian

Let’s add additional subuids/subgids for the root user.

usermod --add-subuids 200000-265535 root
usermod --add-subgids 200000-265535 root
# to remove subgroups
# usermod --del-subuids 200000-265535 root
# usermod --del-subgids 200000-265535 root

There are a lot of articles on the Internet about improving OpenVPN speed, and often they are all focused on the settings of the server-client itself, packet sizes, encryption algorithms or disabling them. Everyone compares OpenVPN to a WireGuard. WireGuard works in kernel space and that’s what determines everything. Compared to userspace for openvpn. But that’s not quite true.

Here I must immediately clarify, that the given method of solving the problem is specific for virtual machines with small memory size, from 1Gb to 8Gb, in other cases you need to compare memory, link bandwidth and speed.

Here is a list of dynamically set values ​​relative to the system memory size:

• sysctl net.core.rmem_default
• sysctl net.core.rmem_max
• sysctl net.core.wmem_default
• sysctl net.core.wmem_max
• sysctl net.core.somaxconn
• sysctl net.core.netdev_max_backlog
• sysctl net.core.optmem_max
• sysctl net.ipv4.udp_mem
• sysctl net.ipv4.udp_rmem_min
• sysctl net.ipv4.udp_wmem_min
• sysctl net.ipv4.tcp_mem
• sysctl net.ipv4.tcp_rmem
• sysctl net.ipv4.tcp_wmem
• sysctl net.ipv4.tcp_synack_retries
• sysctl net.ipv4.tcp_keepalive_time
• sysctl net.ipv4.tcp_max_tw_buckets