= Info for developers =

== Command Line Tool ==

Example:

 # pct create 200 debian-7.0-standard_7.0-2_i386.tar.gz
 # pct start 200
 # pct enter 200
 # pct stop 200
 # pct destroy 200

You can get detailed help with:

 # pct help -v
 
== Container names ==

We use integers values for container names (and do not allow to use
arbitrary names for containers).

== LXC Configuration ==

We store LXC container configurations on the cluster file system:

 /etc/pve/nodes/<nodeid>/lxc/<CTID>/config

There is a symbolic link for the local node at

 /etc/pve/lxc => /etc/pve/nodes/<localhost>/lxc

We store PVE related configuration using prefix 'pve', for example:

 # lxc config for container 105
 lxc.include = /usr/share/lxc/config/debian.common.conf
 lxc.utsname = ct1
 pve.disksize = 8
 pve.volid = local:105/vm-105-rootfs.raw
 # network config
 lxc.network.type = veth
 pve.network.bridge = vmbr0
 pve.network.gw = 192.168.2.1
 lxc.network.hwaddr = 86:5D:0B:28:E6:23
 pve.network.ip = 192.168.3.106/20
 lxc.network.name = eth0
 lxc.network.veth.pair = veth105.0

Those 'pve.network' entrioes are used by the PVE::LXCSetup classes to
configure the network inside the containers.

We only allow 'veth' networks, and use 'lxc.network.veth.pair' to
uniquely identify the network withing the configuration file

 veth<vmid>.0 => net0
 veth<vmid>.1 => net1
 veth<vmid>.2 => net2
 ...


== CRIU ==

CRIU (1.5.2) does not work well with kernel 3.10.0, so checkpoint/restore
and live migration does not work.

= FAQ =

* Why not LXD

- LXD uses a local database to store configuration files, which simply
  does not work with our distributed configuration file system
  (pmxcfs)

- We want to use our existing libraries (i.e. Storage). Also see:
  https://lists.linuxcontainers.org/pipermail/lxc-users/2015-June/009441.html
  where they write: "Lxd will not be as flexible as lxc in many ways,
  including with respect to backing stores."

  We have a different goal, and want to support many new storage technologies
  like zfs, ceph, ...
  
- It is a wrapper around LXC, and only provides a REST API and new CLI
  tool. But Proxmox VE already provides a full featured API, and CLI tools
  are automatically generated from that API.