Docker inside CT vz7
Since Virtuozzo 7 kernel 3.10.0-327.18.2.vz7.14.7 it is possible to run Docker inside containers. This article describes how.
This page is applicable for Virtuozzo 7 (for OpenVZ 6 see here).
Prerequisites
- Kernel 3.10.0-327.18.2.vz7.14.7 or later version
- Kernel modules veth and overlay loaded on host
To enable veth and overlay modules please run:
modprobe veth modprobe overlay
Note: if you use kernel >= 3.10.0-327.18.2.vz7.14.25, you need to allow using "overlayfs" inside a Virtuozzo Container:
echo 1 > /proc/sys/fs/experimental_fs_enable
This is a temporary step, it will be dropped once overlayfs is proved to be absolutely safe to run in any vz7 Container.
Limitations
- Only overlay and vfs Docker graph drivers are currently supported. Recommended driver is overlay. To enable overlayfs Storage Driver for docker engine inside CT please read here https://docs.docker.com/engine/userguide/storagedriver/selectadriver/
- Checkpointing and live migration of a container with Docker containers inside is not supported yet (to be done)
Container tuning
- Turn on bridge feature to allow docker creating bridged network inside container:
prlctl set $veid --features bridge:on
- Setup Container veth-based network (Container must be veth-based, not venet-based):
prlctl set $veid --device-add net --network Bridged --dhcp yes
- Allow all iptables modules to be used in containers:
prlctl set $veid --netfilter=full
Docker install
To install docker inside container please use Docker Installation Guide for your OS https://docs.docker.com/v1.11/engine/installation/
