• lxd and adjusting size of root device

    , , ,
    kayama

    That’s normal. With LXD 2.9 and the storage pool changes, LXD stopped generating automatic «root» devices for the containers, instead relying on inheritance from the default profile.

    So in LXD < 2.9, every container had a local «root» device which you could then set properties directly on. With those LXD versions, adding a «root» device to your default profile would be entirely ignored as all containers would override it.

    In LXD > 2.9, containers don’t have any devices by default, they instead rely on inheritance. Meaning that if you want to override it, you have to add a new device to the container with the same name so that it overrides the one coming from the profiles.

    «lxc config show NAME» vs ” lxc config show –expanded NAME ” is pretty useful to see how this all works.

    © https://discuss.linuxcontainers.org/u/stgraber

  • Building an LXC Server

    , , ,
    kayama

    Building an LXC Server on Ubuntu with ZFS and a container with public IP address

    First update Ubuntu

    1
    2
    3
    apt-get update
     
    apt-get dist-upgrade

    Setup ZFS

    1
    2
    3
    4
    5
    apt-add-repository ppa:zfs-native/stable
     
    apt-get update
     
    apt-get install ubuntu-zfs

    Configure LXC

    1
    sudo apt-get install lxc

    Configure ZFS

    Create ZFS pool:

    1
    sudo zpool create -f tank /dev/sdX

    Keep in mind that deduplication takes much more memory and sometimes CPU.

    The rule of Thumb says to have 1GB of Ram per TB of Data. For deduplicated ZPools you actually should have 5 GB of Ram for 1TB of Data. I don’t use it.

    1
    zfs set dedup=on tank

    Turn on compression and create fs:

    1
    2
    3
    4
    5
    6
    7
    8
    9
    zfs set compression=on tank
     
    zpool set feature@lz4_compress=enabled tank
     
    zfs set compression=lz4 tank
     
    zfs create tank/lxc
     
    zfs create tank/lxc/containers

    To configure LXC to use ZFS as the backing store and set the default LXC path, add the following to /etc/lxc/lxc.conf:

    1
    2
    3
    lxc.lxcpath = /tank/lxc/containers
     
    lxc.bdev.zfs.root = tank/lxc/containers

    Creating a Container

    Create the first container by doing:

    1
    lxc-create -t ubuntu -n node.name -B zfs

    Setup Bridged Network

    1
    apt-get install bridge-utils

    Important Commands

    Show bridge interfaces:

    1
    brctl show

    Simple Bridge

    This setup can be used to connect multiple network interfaces. The bridge acts as a switch: each additional network interface is directly connected to the physical network.

    Edit /etc/network/interfaces, remove eth0, add br0.

    For dynamic IP:

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    #auto eth0
     
    #iface eth0 inet dhcp
     
    auto br0
     
    iface br0 inet dhcp
     
    bridge_ports eth0
     
    bridge_stp off
     
    bridge_fd 0
     
    bridge_maxwait 0

    For static IP:

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    auto br0
     
    iface br0 inet static
     
    bridge_ports eth0
     
    bridge_stp off
     
    bridge_fd 0
     
    bridge_maxwait 0
     
    address 192.168.0.101
     
    netmask 255.255.255.0
     
    network 192.168.0.0
     
    broadcast 192.168.0.255
     
    gateway 192.168.0.254
     
    dns-nameservers 8.8.8.8 8.8.4.4

    reboot server

    Is all OK?

    Edit /tank/lxc/containers/node.name/config

    1
    2
    3
    4
    5
    6
    7
    lxc.network.type = veth
     
    lxc.network.flags = up
     
    lxc.network.link = br0
     
    lxc.network.hwaddr = 00:16:3e:30:fa:4a

    start the node:

    1
    lxc-start -n node.name -d

    connect to the node:

    1
    lxc-console -n node.name

    On the lxc node /etc/network/interfaces:

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    auto eth0
     
    iface eth0 inet static
     
    address 192.168.0.102
     
    netmask 255.255.255.0
     
    network 192.168.0.0
     
    broadcast 192.168.0.255
     
    gateway 192.168.0.254
     
    dns-nameservers 8.8.8.8 8.8.4.4

    It’s possible to use static IP address in node config and use dhcp inside the node, that works too.

    But IPv6 didn’t work inside the node, I disabled it and then the node stopped receiving IP address at all.

    I had to use static IP.

    I’m going to solve this problem later.