I built and am running a mail server, using dovecot for IMAP4 server and Power DNS (pdns) for DNS authoritative server, and memcached for back-end service for some mail filter. I also use LXC for staging environment to test my mail server, but running those services is not straight forward. My understanding is that it is because some security features of systemd using Linux kernel namespace function conflict with the use of namespace in LXC container. So, if you want to run memcached, dovecot, and pdns via systemd within LXC container, you have to disable some security features of systemd by configuration. My additional configuration to systemd is as follows: root@myhost:/# cat /etc/systemd/system/memcached.service.d/99-ns.conf [Service] ProtectSystem = no ProtectHome = no PrivateDevices = no PrivateTmp = no cat /etc/systemd/system/dovecot.service.d/99-ns.conf [Service] ProtectSystem = no PrivateDevices = no PrivateTmp = no root@myhost:/# grep -v '#' /etc/systemd/system/pdns.s