= lxc =
Linux Containers

 * [[https://linuxcontainers.org/lxc/introduction/]]
 * [[http://www.cyberciti.biz/faq/how-to-create-unprivileged-linux-containers-on-ubuntu-linux/]]
 * [[http://en.wikipedia.org/wiki/LXC]]

LXC (Linux Containers) is an operating system–level virtualization method for running multiple isolated Linux systems (containers) on a single control host.

LXC provides operating system-level virtualization through a virtual environment that has its own process and network space, instead of creating a full-fledged virtual machine. 

== Ubuntu precise i386 container on Slackware 14.2 ==
{{{#!highlight bash
lxc-create -t download -n containerx -- -d ubuntu  -r precise -a i386
#Setting up the GPG keyring
#Downloading the image index
#Downloading the rootfs
#Downloading the metadata
#The image cache is now ready
#Unpacking the rootfs
#
#---
#You just created an Ubuntu container (release=precise, arch=i386, variant=default)
#
#To enable sshd, run: apt-get install openssh-server
#
#For security reason, container images ship without user accounts
#and without a root password.
#
#Use lxc-attach or chroot directly into the rootfs to set a root password
#or create user accounts.
# start a container
lxc-start -n containerx -d
# list containers
lxc-ls --fancy
# spawn a new shell running inside an existing container
lxc-attach -n containerx

# session in containerx 
cat /etc/os-release 
#NAME="Ubuntu"
#VERSION="12.04.5 LTS, Precise Pangolin"
#ID=ubuntu
#ID_LIKE=debian
#PRETTY_NAME="Ubuntu precise (12.04.5 LTS)"
#VERSION_ID="12.04"

# run several commands in the container
lxc-attach -n containerx -- sh -c 'TESTFILE=/tmp/asd;cat $TESTFILE; echo $TESTFILE'
lxc-attach -n containerx -- sh -c 'cat /etc/os-release; dpkg -l;'
# containers are stored under  /var/lib/lxc/

}}}

== Containers in Slackware64 15.0 ==
 * https://linuxcontainers.org/lxc/manpages/man5/lxc.container.conf.5.html
 * https://docs.slackware.com/howtos:misc:lxc

{{{#!highlight bash
su
# list available templates and distros
lxc-create -t download -n NAME
#Setting up the GPG keyring
#Downloading the image index
#
#---
#DIST	RELEASE	ARCH	VARIANT	BUILD
#---
#almalinux	8	amd64	default	20220224_23:09
#almalinux	8	arm64	default	20220224_23:09
#alpine	3.12	amd64	default	20220225_13:00
#alpine	3.12	arm64	default	20220225_13:01
#alpine	3.12	armhf	default	20220225_13:00
#alpine	3.12	i386	default	20220225_13:01
# press ctrl+c to exit
lxc-create -t download -n containery -- -d ubuntu  -r bionic -a i386
lxc-start -n containery -d
lxc-ls --fancy
lxc-attach -n containery
# in the container
lsb_release -a
}}}

=== /etc/cgconfig.conf ===
{{{
group qwerty {
    perm {
        task {
            uid = vitor;
            gid = users;
        }
    admin {
          uid = vitor;
          gid = users;
      }
  }

  cpuset {
      cgroup.clone_children = 1;
      cpuset.mems = 0;
  }
  cpu {}
  cpuacct {}
  blkio {}
  memory { memory.use_hierarchy = 1; }
  devices {}
  freezer {}
  net_cls {}
  perf_event {}
  net_prio {}
  pids {}
}
}}}

=== /etc/cgrules.conf ===
{{{
vitor           *               qwerty/
}}}

=== /etc/subgid ===
{{{
vitor:100000:65537
}}}

=== /etc/subuid ===
{{{
vitor:100000:65537
}}}

=== /etc/default/lxc-net ===
{{{#!highlight bash
USE_LXC_BRIDGE="true"
}}}

=== /etc/lxc/default.conf ===
{{{
lxc.net.0.type = empty
}}}

=== ~/.config/lxc/default.conf ===
{{{
lxc.idmap = u 0 100000 65536
lxc.idmap = g 0 100000 65536

lxc.net.0.type = veth
lxc.net.0.flags = up
lxc.net.0.link = lxcbr0
}}}

=== /etc/rc.d/rc.inet1.conf ===
{{{#!highlight bash
USE_DHCP[0]="yes"
}}}

=== /etc/rc.d/rc.local ===
{{{#!highlight bash
echo 1 > /proc/sys/net/ipv4/ip_forward
/sbin/brctl addbr lxcbr0
/sbin/brctl setfd lxcbr0 0
/sbin/ifconfig lxcbr0 192.168.100.1 netmask 255.255.255.0 promisc up
#/usr/sbin/iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
/usr/sbin/iptables -t nat -A POSTROUTING -o wlan1 -j MASQUERADE
/usr/libexec/lxc/lxc-net start
}}}

=== Test steps ===
{{{#!highlight bash
lxc-create -t download -n containery -- -d alpine  -r 3.16 -a i386
lxc-start -n containery -d
lxc-ls --fancy
lxc-attach -n containery
# commands inside container
ping 8.8.8.8
exit
# show containers filesystems locations
lxc-config lxc.lxcpath
/home/vitor/.local/share/lxc
#
lxc-stop containery
lxc-destroy containery 
}}}

=== setup_ssh_container.sh ===
{{{#!highlight bash
CONTAINER=ssh-container
lxc-stop $CONTAINER
lxc-destroy $CONTAINER
lxc-create -t download -n $CONTAINER -- -d alpine  -r 3.16 -a i386
lxc-execute -n $CONTAINER -- ash -c "echo 'assd' > /t1.txt"
lxc-start -n $CONTAINER -d
lxc-attach -n $CONTAINER -- ash -c "/sbin/apk update"
lxc-attach -n $CONTAINER -- ash -c "/sbin/apk add --update curl wget nano vim shadow openssh"
lxc-attach -n $CONTAINER -- ash -c "mkdir /app"
lxc-attach -n $CONTAINER -- ash -c "echo 'root:screencast' | /usr/sbin/chpasswd"
lxc-attach -n $CONTAINER -- ash -c "echo 'PasswordAuthentication yes' >> /etc/ssh/sshd_config"
lxc-attach -n $CONTAINER -- ash -c "echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config"
lxc-attach -n $CONTAINER -- ash -c "/sbin/rc-update add sshd"
lxc-attach -n $CONTAINER -- ash -c "/sbin/service sshd start"
sleep 5
lxc-ls --fancy | grep $CONTAINER
}}}