yannick

Installation of LXC

RHEL / CentOS

# yum install epel-release
# yum update
# yum install lxc lxc-templates lxc-doc lxc-libs rsync debootstrap
# yum install lxc-extra
# yum install bridge-utils

Ubunt

# apt-get install lxc

Checking

# lxc-checkconfig

Create Bridge Network

/etc/sysconfig/network-scripts/ifcfg-lxcbr0

NAME=lxcbr0
DEVICE=lxcbr0
TYPE=Bridge
BOOTPROTO=static
ONBOOT=yes
IPADDR=192.168.1.1
PREFIX=24
DEFROUTE=no
NM_CONTROLLED=no

Create container

Method1 : Download Images

# lxc-create -n cent-lxc1 -t download -- -d centos -r 7 -a amd64
# lxc-create -t download -n container1 -- -d ubuntu -r trusty -a amd64

Method2 : create image from repo

# ls /usr/share/lxc/templates/
lxc-alpine    lxc-archlinux  lxc-centos  lxc-debian    lxc-fedora  lxc-openmandriva  lxc-oracle  lxc-sshd    lxc-ubuntu-cloud
lxc-altlinux  lxc-busybox    lxc-cirros  lxc-download  lxc-gentoo  lxc-opensuse      lxc-plamo   lxc-ubuntu
# lxc-create -n centos7 -t centos -- --release 7
# lxc-create -t ubuntu -n test01
# lxc-create -n web01 -t download -- -d centos -r 7 -a amd64
# ls /var/lib/lxc/test01/

Container's standard storage location

PATH	Note
/var/lib/lxc	Container's standard storage location
/var/lib/lxcsnap	Standard snapshot storage location
/var/cache/lxc	Standard template cache location
$HOME/.local/share/lxc	Standard storage location for non-privileged containers
$HOME/.local/share/lxcsnap	Typical storage location for non-privileged snapshots
$HOME/.cache/lxc	Standard storage location of non-privileged template cache

Configuraion

Network Namespace

/var/lib/lxc/CONTAINER/config

How to use veth

lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = virbr0                  <- host NIC

How to use macvlan

lxc.network.type = macvlan
lxc.network.macvlan.mode = bridge
lxc.network.flags = up
lxc.network.link = eth0                  <- host NIC
lxc.network.type = macvlan
lxc.network.macvlan.mode = bridge
lxc.network.flags = up
lxc.network.link = ens192                  <- host NIC
lxc.network.hwaddr = fe:e1:e7:96:43:bc     <- container's MAC
lxc.rootfs = /var/lib/lxc/centos7/rootfs

Commands List

Commands	Note
lxc-ls lxc-ls -f <- -f = --fancy
lxc-create -n CONTAINER -t XXXX -- --relese X
lxc-start -n CONTAINER lxc-start -n CONTAINER -d ← start background
lxc-stop -n CONTAINER lxc-stop -k -n CONTAINER ← stop force
lxc-console -n CONTAINER	<Ctrl+a q> to exit
lxc-attach -n CONTAINER
lxc-info -n CONTAINER
lxc-destroy -n container1 lxc-destroy -n container1 -f

Operation

Check container

# lxc-ls 
test-cent1
#
NAME        STATE    IPV4  IPV6  AUTOSTART  
---------------------------------------
test-cent1  STOPPED  -     -     NO    
#
# lxc-info -n  test-cent1
Name:           test-cent1
State:          STOPPED
#

Change Passwd

# chroot /var/lib/lxc/centos7/rootfs passwd

Start

# lxc-start -n test01 -d   <- start with damon
# lxc-console -n test01    <- connection with console

Auto-start

# vi /var/lib/lxc/CONTAINER/config
...
lxc.start.auto = 1      #enable
lxc.start.delay = 5     #delay in second to wait after starting the container
lxc.start.order = 100   #priority of the container, higher value means starts earlier

shutdown

# lxc-shutdown -n test-container-101

Clone LXC Container

# lxc-stop -n  ORIGINAL
# lxc-clone -o ORIGINAL -n NEW

Snapshot LXC Container

You don't snapshot with directory-backend.

Snapshot

# lxc-snapshot -n CONTAINER -L -C   <- Ceck
# lxc-snapshot -n CONTAINER -c COMMENT
# lxc-snapshot -n CONTAINER -L -C   <- Ceck

Restore

# lxc-snapshot -n CONTAINER -L -C   <- Ceck
# lxc-snapshot -n CONTAINER -r snap0
# lxc-snapshot -n CONTAINER -r snap0 NEWCONTAINER

Tips

Check the temporary root password

# cat /var/lib/lxc/centos_lxc/tmp_root_pass

Reset the root password using the following command.

# chroot /var/lib/lxc/centos_lxc/rootfs passwd

Change Kernel Parameters for many containers

# vi /etc/sysctl.conf

...
kernel.threads-max = 100000
kernel.pid_max  = 131072
vm.max_map_count = 300000  #65,530 default 
...
# vi /etc/security/limits.d/90-nproc.conf