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How to create a LXC Ubuntu root filesystem for VNX

Basic installation

Follow this procedure to create a Ubuntu based LXC root filesystem for VNX. The procedure has been tested with Ubuntu versions from 13.10 to 18.04.

  • Create the rootfs with:
  • lxc-create -t ubuntu -n vnx_rootfs_lxc_ubuntu-18.04

    Note1: The default username/password is ubuntu/ubuntu.
    Note2: This method creates an image with the same architecture (32 or 64 bits) as the host. To create a 32 bits image in a 64 bits host, the only method known to work is to follow the procedure described in this page inside a KVM 32 bits virtual machine.

  • Move the rootfs to VNX filesystems directory:
  • mv /var/lib/lxc/vnx_rootfs_lxc_ubuntu-18.04/ /usr/share/vnx/filesystems/
  • If using Ubuntu 17.10 or newer (lxc version 2.1 or newer), convert the configuration file to old config format (VNX converts back to the newer format if needed when starting containers):
  • lxc.rootfs.path -> lxc.rootfs -> lxc.utsname -> -> -> ->
  • Edit the rootfs configuration file (/usr/share/vnx/filesystems/vnx_rootfs_lxc_ubuntu-16.04/config) to reflect the directory change:
  • lxc.rootfs = /usr/share/vnx/filesystems/vnx_rootfs_lxc_ubuntu-16.04/rootfs
    lxc.mount  = /usr/share/vnx/filesystems/vnx_rootfs_lxc_ubuntu-16.04/fstab
  • Create fstab file (if not created):
  • touch vnx_rootfs_lxc_ubuntu-16.04/fstab
  • Start the new rootfs to configure it and install new software:
  • lxc-start -n vnx -F -f /usr/share/vnx/filesystems/vnx_rootfs_lxc_ubuntu-16.04/config
  • Once the VM has started, make login (ubuntu/ubuntu) and:
    • Add VNX user and change the passwords:
    • sudo adduser vnx
      sudo adduser vnx sudo
      sudo passwd root
    • Update and install software:
    • sudo apt-get update
      sudo apt-get dist-upgrade
      sudo apt-get install aptsh openssh-server traceroute telnet nmap apache2 wget tcpdump net-tools ifupdown
      update-rc.d -f apache2 remove   # to avoid automatic start
      systemctl disable apache2       # in newer systems
    • Change VM name in hosts and hostname files:
    • sudo vi /etc/hosts         # change name to vnx
      sudo vi /etc/hostname      #     "
    • Enable root access through textual consoles with:
    • echo "pts/0" >> /etc/securetty
      echo "pts/1" >> /etc/securetty
      echo "pts/2" >> /etc/securetty
      echo "pts/3" >> /etc/securetty
    • Important: edit /etc/network/interfaces and coment "inet dhcp" lines to avoid delays at startup. Besides, edit /etc/init/failsafe.conf and change all "sleep XX" commands to "sleep 1".
  • Disable auto-upgrades if enabled:
  • sed -i -e 's/"1"/"0"/g' /etc/apt/apt.conf.d/20auto-upgrades
  • Delete the "mesg n" command in root's .profile to avoid the nasty message "mesg: ttyname failed: No such device" when executing commands with lxc-attach:
  • sed -i '/^mesg n/d' /root/.profile
  • Exit and login again with user vnx/xxxx to delete ubuntu user:
  • sudo deluser ubuntu
  • Stop the VM with:
  • halt
  • If you want to pack the root filesystem into a tar file, use the following command:
  • tar --numeric-owner -czpf vnx_rootfs_lxc_ubuntu-16.04-v025.tgz vnx_rootfs_lxc_ubuntu-16.04-v025
  • Optionally, create a short link to the rootfs:
  • cd /usr/share/vnx/filesystems
    ln -s vnx_rootfs_lxc_ubuntu-16.04 rootfs_lxc