LXD
LXD is a next generation system container manager. The core of LXD is a privileged daemon which exposes a REST API over a local Unix socket as well as over the network (if enabled)[1].
LXD isn't a rewrite of LXC; in fact it is built on top of LXC to provide a new, better user experience. Under the hood, LXD uses LXC through liblxc and its Go binding to create and manage the containers. It's basically an alternative to LXC's tools and distribution template system with the added features that come from being controllable over the network.
For those new to container technology, it can be useful to first read the LXC Virtualization Concepts article.
Key features of LXD include:
- It prefers to launch unprivileged containers (secure by default).
- A command-line client (lxc) interacts with a daemon (lxd).
- Configuration is made intuitive and scriptable through cascading profiles.
- Configuration changes are performed with the lxc command (not config files).
- Multiple hosts can be federated together (with a certificate-based trust system).
- A federated setup means that containers can be launched on remote machines and live-migrated between hosts (using CRIU technology).
- It is usable as a standalone hypervisor or integrated with Openstack Nova
In December 2023, LXD was relicensed as AGPLv3. Some users might wish to consider the app-containers/incus project, a fork of LXD maintained by the Linux Containers team, which remains under the Apache 2.0 license; information about the initial release, including changes from LXD, is available here.
Quick start (single host)
Prepare the system
Kernel configuration
It is a good idea to have most kernel flags required by app-containers/lxc and sys-process/criu.
root #ebuild /var/db/repos/gentoo/app-containers/lxc/lxc-4.0.6.ebuild setup... * Checking for suitable kernel configuration options... * CONFIG_NETLINK_DIAG: needed for lxc-checkpoint * CONFIG_PACKET_DIAG: needed for lxc-checkpoint * CONFIG_INET_UDP_DIAG: needed for lxc-checkpoint * CONFIG_INET_TCP_DIAG: needed for lxc-checkpoint * CONFIG_UNIX_DIAG: needed for lxc-checkpoint * CONFIG_CHECKPOINT_RESTORE: needed for lxc-checkpoint * Please check to make sure these options are set correctly. * Failure to do so may cause unexpected problems. |ebuild /var/db/repos/gentoo/sys-process/criu/criu-1.6.1.ebuild setup ...
Do you have plans for running systemd-based unprivileged containers? You will probably need to enable the "Gentoo Linux -> Support for init systems, system and service managers -> systemd" (CONFIG_GENTOO_LINUX_INIT_SYSTEMD)
Emerge
root #emerge --ask app-containers/lxdAuthorize a non-privileged user
All members of the lxd group can use any of the available containers, irrespective of who created the container.
root #usermod --append --groups lxd larryThis will allow a non-root user to interact with the control socket which is owned by the lxd UNIX group.
For the group change to take effect, users need to log out and log back in again.
Configure subuid/subgid
LXD requires that subuids and subgids for the lxd user are propely configured. An overview for the recommended configuration of subuid/subgids is given in the wiki - Subuid subgid.
Start the daemon
OpenRC
The lxd service is available and can be added to the default runlevel:
root #rc-update add lxd default
root #rc-service lxd start
systemd
The systemd unit file has also been installed.
Configuration
/etc/conf.d/lxd has a few available options related to debug output, but the defaults are adequate for this quick start.'
Setup storage and networking
root #lxd initWould you like to use LXD clustering? (yes/no) [default=no]: Do you want to configure a new storage pool (yes/no) [default=yes]? Name of the new storage pool [default=default]: Name of the storage backend to use (dir, lvm) [default=dir]: Would you like to connect to a MAAS server? (yes/no) [default=no]: Would you like to create a new network bridge (yes/no) [default=yes]? no Would you like to configure LXD to use an existing bridge or host interface? (yes/no) [default=no]: Would you like LXD to be available over the network? (yes/no) [default=no]: Would you like stale cached images to be updated automatically? (yes/no) [default=yes]: Would you like a YAML "lxd init" preseed to be printed? (yes/no) [default=no]:
Configure the bridge
If a new bridge was created by lxd init, start it now.
root #rc-service net.lxcbr0 startIf desired, the bridge can be configured to come up automatically in the runlevel.
root #rc-update add net.lxcbr0 defaultLaunch a container
Add an image repository at a remote called "images":
user $lxc remote add images https://images.linuxcontainers.orgThis is an untrusted remote, which can be a source of images that have been published with the --public flag. Trusted remotes are also possible, and are used as container hosts and also to serve private images. This specific remote is not special to LXD; organizations may host their own images.
user $lxc image list images:+--------------------------------+--------------+--------+-------------------------+---------+-------------------------------+ | ALIAS | FINGERPRINT | PUBLIC | DESCRIPTION | ARCH | UPLOAD DATE | +--------------------------------+--------------+--------+-------------------------+---------+-------------------------------+ | | 3ae185265c53 | yes | Centos 6 (amd64) | x86_64 | Aug 29, 2015 at 10:17pm (CDT) | | | 369ac13f390e | yes | Centos 6 (amd64) | x86_64 | Sep 3, 2015 at 12:17pm (CDT) | | centos/6/amd64 (1 more) | 8e54c679f1c2 | yes | Centos 6 (amd64) | x86_64 | Sep 3, 2015 at 10:17pm (CDT) | | | 755542362bbb | yes | Centos 6 (i386) | i686 | Aug 29, 2015 at 10:19pm (CDT) | | | b4d26dbc6567 | yes | Centos 6 (i386) | i686 | Sep 3, 2015 at 12:20pm (CDT) | | centos/6/i386 (1 more) | 21eeba48a2d4 | yes | Centos 6 (i386) | i686 | Sep 3, 2015 at 10:19pm (CDT) | | | 9fe7ffdbc0ae | yes | Centos 7 (amd64) | x86_64 | Aug 29, 2015 at 10:22pm (CDT) | | | d750b910e62d | yes | Centos 7 (amd64) | x86_64 | Sep 3, 2015 at 12:23pm (CDT) | | centos/7/amd64 (1 more) | 06c4e5c21707 | yes | Centos 7 (amd64) | x86_64 | Sep 3, 2015 at 10:22pm (CDT) | | | ee229d68be51 | yes | Debian jessie (amd64) | x86_64 | Aug 29, 2015 at 6:29pm (CDT) | | | 69e457e1f4ab | yes | Debian jessie (amd64) | x86_64 | Sep 2, 2015 at 6:34pm (CDT) | | debian/jessie/amd64 (1 more) | 2ddd14ff9422 | yes | Debian jessie (amd64) | x86_64 | Sep 3, 2015 at 6:30pm (CDT) | | | 9fac01d1e773 | yes | Debian jessie (armel) | armv7l | Aug 31, 2015 at 7:24pm (CDT) | | | 67f4fedafd2f | yes | Debian jessie (armel) | armv7l | Sep 1, 2015 at 7:24pm (CDT) | ...
There are Gentoo images in the list, although they are not maintained by the Gentoo project. LXC users may recognize these images as the same ones available using the "download" template.
user $lxc launch images:centos/6/amd64 mycentos6Creating mycentos6 done. Starting mycentos6 done.
user $lxc list+-----------+---------+----------------+------+-----------+-----------+ | NAME | STATE | IPV4 | IPV6 | EPHEMERAL | SNAPSHOTS | +-----------+---------+----------------+------+-----------+-----------+ | mycentos6 | RUNNING | 192.168.43.240 | | NO | 0 | +-----------+---------+----------------+------+-----------+-----------+
A shell can be run in the container's context.
user $lxc exec mycentos6 /bin/bash[root@mycentos6 ~]# ps faux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 428 0.0 0.0 11500 2648 ? Ss 16:13 0:00 /bin/bash root 440 0.0 0.0 13380 1888 ? R+ 16:13 0:00 \_ ps faux root 1 0.0 0.0 19292 2432 ? Ss 16:03 0:00 /sbin/init root 188 0.0 0.0 4124 1316 console Ss+ 16:03 0:00 /sbin/mingetty --nohangup console root 228 0.0 0.0 9180 1392 ? Ss 16:03 0:00 /sbin/dhclient -H mycentos6 -1 -q -lf /var/lib/dhclient/dhclient-eth0.leases -pf /var/run/dhc root 278 0.0 0.0 171372 2544 ? Sl 16:03 0:00 /sbin/rsyslogd -i /var/run/syslogd.pid -c 5 root 439 0.0 0.0 4120 1472 ? Ss 16:13 0:00 /sbin/mingetty --nohangup /dev/tty[1-6]
While the container sees its processes as running as the root user, running ps on the host shows the processes running as UID 1000000. This is the advantage of unprivileged containers: root is only root in the container, and is nobody special in the host. It is possible to manipulate the subuid/subgid maps to allow containers access to host resources (for example, write to the host's X socket) but this must be explicitly allowed.
Make your own container images
Use a tool called Distrobuilder#Create_your_own_container_images.
Configuration
Configuration of containers is managed with the lxc config and lxc profile commands. The two commands provide largely the same capabilities, but lxc config acts on single containers while lxc profile configures a profile which can be used across multiple containers.
Importantly, containers can be launched with multiple profiles. The profiles have a cascading effect so that a profile specified later in the list can add, remove, and override configuration values that were specified in a earlier profile. This can allow for complex setups where groups of containers can be specified which share some properties but not others.
user $lxc profile listdefault migratable
user $lxc profile show defaultname: default
config: {}
devices:
eth0:
nictype: bridged
parent: lxcbr0
type: nicThe default profile is applied if no profile is specified on the command line. In the quick start, the lxc launch omitted the profile, and so was equivalent to:
user $lxc launch images:centos/6/amd64 mycentos6 --profile defaultNotice that that the default profile only specifies that a container should have a single NIC which is bridged onto an existing bridge lxcbr0. So, having a bridge with that name is not a hard requirement, it just happens to be named in the default profile.
Available configuration includes limits on memory and CPU cores, and also devices including NICs, bind mounts, and block/character device nodes.
Configuration is documented in /usr/share/doc/lxd-0.16/specs/configuration.md (substitute the correct version of course).
All documented configuration options are not yet implemented, and only by inspecting source code can a user know which devices might be expected to work. For example, at the time of this writing:
- The only legal nictype for an interface is "bridged"
- The "disk" device type can only perform bind mounts, and only on a directory.
- Setting limits.memory seems not to work, although limits.cpus does
Example
Here a container is launched with the default profile and also a "cpusandbox" profile which imposes a limit of one CPU core. A directory on the host is also bind-mounted into the container using the container-specific lxc config command.
First, prepare a reusable profile.
user $lxc profile create cpusandboxProfile cpusandbox created
user $lxc profile set cpusandbox limits.cpu 1lxc config requires a container name, so a container is initialized.
user $lxc init 8e54c679f1c2 confexample --profile default --profile cpusandboxCreating confexample done.
The 8e54c679f1c2 argument represents an image fingerprint obtained with
lxc image list. It's possible to give friendly aliases to images.In the quick start above the
lxc launch was invoked, which is a shorthand to lxc init followed by lxc start. The latter is used in this example so that lxc config can be invoked before the container is first started.In this example a host directory /tmp/shared is bind-mounted into the container at /tmp. While this could be configured in a profile, instead it will be considered an exclusive feature for that container.
user $mkdir /tmp/shareduser $touch /tmp/shared/hello.txtSet the directory to be owned by the container's root user (really UID 1000000 in the host).
user $sudo chown -R 1000000:1000000 /tmp/shareduser $lxc config device add confexample sharedtmp disk path=/tmp source=/tmp/sharedDevice sharedtmp added to confexample
user $lxc start confexampleuser $lxc exec confexample ls /tmphello.txt
Multi-host setup
Two hosts on a network, alpha and beta, are running the lxd daemon. The goal is to run commands on alpha which can manipulate containers and images on either alpha or beta.
Resolvable names are prepared for readability but it also works to use IP addresses.
Setup
Configure the daemon on the remote to listen over HTTPS instead of the default local Unix socket.
beta $lxc config set core.https_address beta:8443Restart the daemon after this step, and be sure that the firewall will accept incoming connections as specified.
On beta configure a trust password, which is only used until certificates are exchanged.
beta $lxc config set core.trust_password Sieth9gei7ahm2raAdd the beta remote to alpha.
alpha $lxc remote add beta https://beta:8443Certificate fingerprint: 7a 76 5b c6 c6 eb 4e db 20 7f 31 bb 1d 11 ca 2d c5 d8 7d cf 41 c0 a0 1f aa 8b c3 f0 18 79 d3 a3 ok (y/n)? y Admin password for beta: Client certificate stored at server: beta
Result
It is now possible to perform actions on beta from alpha using the remote: syntax
alpha $lxc list beta:alpha $lxc remote list beta:alpha $lxc launch beta:centos6 beta:container0alpha $lxc info beta:container0To copy containers or images, the source ("from") host must have its daemon listening via HTTPS not Unix socket.
alpha $lxc image copy beta:gentlean local:alpha $lxc image copy centos6 beta:error: The source remote isn't available over the network
As long as commands were run from alpha, it was never necessary to add alpha as a remote to either host. It was also not necessary to change alpha's core.https_address config setting to use HTTPS instead of Unix socket unless it is the source of a container or image copy.
Configuration settings and profiles are only set on the local host. They can be copied to remotes but this is manual and error-prone unless configuration managment tools are used to propagate these values. Consider requiring all commands to be run from a single host with its local config database for ease of administration.
Virtual machines
LXD can use QEMU to run virtual machines. The default image server already hosts many virtual machine alternatives, even pre-configured desktop vm images. You'll find virtual machine images by checking the "TYPE"-field. Many pre-configured desktop images can be found with a "desktop" in their description.
user $lxc image list images: | grep -i desktopRunning and operating virtual machines requires QEMU to be installed, with the following USE-flags enabled: spice, usbredir, virtfs.
/etc/portage/package.use/qemuapp-emulation/qemu spice usbredir virtfs
root #emerge --ask app-emulation/qemuFor graphical sessions to work in your virtual machine, i.e. logging to a desktop, either app-emulation/virt-viewer or net-misc/spice-gtk needs to be installed.
root #emerge --ask app-emulation/virt-viewerThe following kernel options are needed: CONFIG_MACVTAP, CONFIG_VHOST_VSOCK, CONFIG_KVM and either CONFIG_KVM_AMD or CONFIG_KVM_INTEL depending on your CPU. Please see QEMU#Kernel for more accurate config options. You'll also need to enable virtualization in your BIOS, otherwise you'll get an error message of "KVM: disabled by BIOS". Basically, make sure /dev/kvm exists before trying to launch a virtual machine. And setup QEMU properly so it works.
Get a virtual machine image, and launch it:
user $lxc launch images:opensuse/15.3/desktop-kde opensuse-kde --vmThe --vm flag is mandatory.
Currently Gentoo doesn't ship required files for secureboot, and some distros require them by default. You can override this with -c security.secureboot=false, in other words, lxc launch images:opensuse/15.3/desktop-kde opensuse-kde --vm -c security.secureboot=false
Alternatively do it manually: lxc config edit opensuse-kde and add security.secureboot: "false" under config: section.
Access the shell of your virtual machine:
user $lxc exec opensuse-kde -- su --loginAccess the desktop/GUI of your virtual machine:
user $lxc console opensuse-kde --type=vga
Allocating resources in a virtual machine
By default the virtual machine images are very starved. You may need to use lxc or external tools to give them more resources. You can configure many resources similarly to containers, and there are tons of these configuration options. Please refer to upstream documentation about adjusting resources for lxd containers.
CPU
Give the VM 8 cores:
user $lxc config set my-vm limits.cpu 8Or to allow it to use 50 % of CPU capability:
user $lxc config set my-vm limits.cpu.allowance 50% Give it the lowest CPU priority:
user $lxc config set my-vm limits.cpu.priority 0Disk size
Simply the following should work when the VM is off:
user $lxc config device set my-vm root size=20GBThese profile settings can be used to create VMs with bigger disk sizes. Make sure the profile is inherited by the VM in question.
user $lxc profile show bigger-vm-diskconfig: {}
description: VM Profile for a bigger root disk
devices:
root:
path: /
pool: default
size: 50GB
type: disk
user $lxc config show my-vm... profiles: - default - bigger-vm-disk ...
If it does not, the manual method below is a more sureway to get it done:
On the host resize image with qemu-img.
user $cd ~/lxd/virtual-machines/gentoo-openrc-vm/
user $qemu-img resize root.img 20GDepending on image, qemu-img resize -f raw root.img 20G might be required instead.
Now move on to the virtual machine.
user $lxc start gentoo-vm
user $lxc exec gentoo-vm bashgentoo-openrc-vm #emerge -av sys-fs/growpart gentoo-openrc-vm #df -h
gentoo-openrc-vm #growpart /dev/sda 2
gentoo-openrc-vm #resize2fs /dev/sda2
gentoo-openrc-vm #df -hMemory
Give your VM 8 GB of memory:
user $lxc config set my-container limits.memory 8GBAlso accepts MB.
Network
systemd generally "just works".
Whether you want to receive an IP address via dhcp or statically, the Handbook has written steps that work in a virtual machine. Get your interface:
root #ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
link/ether 74:56:3c:64:cf:26 brd ff:ff:ff:ff:ff:ff
gentoo-openrc-vm #cd /etc/init.d gentoo-openrc-vm #rm net.eth0
gentoo-openrc-vm #ln -s net.lo net.enp5s0
gentoo-openrc-vm #/etc/init.d/net.enp5s0 start
gentoo-openrc-vm #rc-update add enp5s0 defaultAdvanced features
Live migration
TODO
Automatic BTRFS integration
When LXD detects that /var/lib/lxd is on a Btrfs filesystem, it uses Btrfs' snapshot capabilities to ensure that images, containers and snapshots share blocks as much as possible. No user action is required to enable this behavior.
When the container was launched in the Quick Start section above LXD created subvolumes for the image and container. The container filesystem is a copy-on-write snapshot of the image.
root #btrfs subvolume list /ID 330 gen 4518 top level 5 path var/lib/lxd/images/8e54c679f1c293f909c66097d97de23c66a399d2dc396ade92b3b6aae1c7 ID 331 gen 4595 top level 5 path var/lib/lxd/containers/mycentos6
root #btrfs subvolume show /var/lib/lxd/images/8e54c679f1c293f909c66097d97de23c66a399d2dc396ade92b3b6a
/var/lib/lxd/images/8e54c679f1c293f909c66097d97de23c66a399d2dc396ade92b3b6aae1c732fe.btrfs
Name: 8e54c679f1c293f909c66097d97de23c66a399d2dc396ade92b3b6aae1c732fe.btrfs
UUID: 5530510e-2007-f146-9e0b-8c05480d63de
Parent UUID: -
Received UUID: -
Creation time: 2015-09-04 15:03:32 -0500
Subvolume ID: 330
Generation: 4518
Gen at creation: 4517
Parent ID: 5
Top level ID: 5
Flags: -
Snapshot(s):
var/lib/lxd/containers/mycentos6
Making a snapshot of the running container filesystem creates another copy-on-write snapshot.
user $lxc snapshot mycentos6 firstsnaproot #btrfs subvolume list /ID 330 gen 4518 top level 5 path var/lib/lxd/images/8e54c679f1c293f909c66097d97de23c66a399d2dc396ade92b3b6aae1c7 ID 331 gen 4595 top level 5 path var/lib/lxd/containers/mycentos6 ID 332 gen 4584 top level 5 path var/lib/lxd/snapshots/mycentos6/firstsnap
root #btrfs subvolume show /var/lib/lxd/containers/mycentos6/var/lib/lxd/containers/mycentos6
Name: mycentos6
UUID: fe6bfd65-d911-e449-a1df-be42d2997f4a
Parent UUID: 5530510e-2007-f146-9e0b-8c05480d63de
Received UUID: -
Creation time: 2015-09-04 15:03:39 -0500
Subvolume ID: 331
Generation: 4595
Gen at creation: 4518
Parent ID: 5
Top level ID: 5
Flags: -
Snapshot(s):
var/lib/lxd/snapshots/mycentos6/firstsnap
/dev/lxd/sock
A socket is bind-mounted into the container at /dev/lxd/sock. It serves no critical purpose, but is available to users as a means to query configuration information about the container.
Graphical (X) applications in a container
It is possible to run GUI applications in a container. Edit container's config,
user $lxc config edit your-container-nameAdd the following:
config:
environment.DISPLAY: :0.0
...
...
devices:
X0:
path: /tmp/.X11-unix
source: /tmp/.X11-unix
type: disk
mygpu:
type: gpu
...
...
DISPLAY environment variable can be seen from a host, with echo $DISPLAY. It is also better to share the directory /tmp/.X11-unix instead of individual files under /tmp/.X11-unix/*.
For container to be allowed to attach into host's Xsession, issue xhost +local: command in the host.
Important: systemd containers will automount /tmp as tmpfs in the container, overwriting your setting here! Either manually unmount /tmp to find your socket, or do the following: Inside the container:
user $cp /usr/lib/tmpfiles.d/x11.conf /etc/tmpfiles.d/user $$EDITOR /etc/tmpfiles.d/x11.confModified version:
/etc/tmpfiles.d/x11.conf# D! /tmp/.X11-unix 1777 root root 10d
D! /tmp/.ICE-unix 1777 root root 10d
D! /tmp/.XIM-unix 1777 root root 10d
D! /tmp/.font-unix 1777 root root 10d
# Unlink the X11 lock files
# r! /tmp/.X[0-9]*-lock
So comment the following lines:
D! /tmp/.X11-unix 1777 root root 10d ... r! /tmp/.X[0-9]*-lock
Stop and start your container, relogin into it. You can of course edit /usr/lib/tmpfiles.d/x11.conf but it's going to be overwritten whenever systemd updates inside the container. See the bug report about this issue.
Troubleshooting
First things to do when facing problems is to check the containers log, lxd's log and system log.
user $lxc start <instance_name> --debuguser $lxc info <instance_name> --show-logAttach immediately to systart:
user $lxc start <instance_name> ; lxc console <instance_name>By default lxd's logs can be found from /var/log/lxd/ - this can also be modified from conf.d and service files.
Containers freeze on 'lxc stop' with OpenRC (+ SysVinit)
If the container freezes during the stop command with
user $lxc stop mycontainerwhile using OpenRC, try to turn it off directly with poweroff:
user $lxc exec mycontainer -- poweroffIf that works, edit the /etc/inittab file in the container adding following part:
/etc/inittabpf:12345:powerwait:/sbin/halt
Shutdown the container with poweroff, and next time it is booted, the container should work like normal and lxc stop should work as expected. Be careful when doing world updates to not blindly merge changes to /etc/inittab.
Running systemd based containers on OpenRC hosts
To support systemd guests, e.g. ubuntu/debian/arch linux containers, on an OpenRC system, the host must be modified to support the systemd cgroup. It is recommended to use cgroupsv2 as most containers support it and OCI runtimes crun and runc also expect cgroupsv2 to be present.
To enable the cgroupsv2 modify /etc/rc.conf to set rc_cgroup_mode="unified" and uncomment and add rc_cgroup_controllers="systemd":
/etc/rc.conf...
...
...
##############################################################################
# LINUX CGROUPS RESOURCE MANAGEMENT
# This sets the mode used to mount cgroups.
# "hybrid" mounts cgroups version 2 on /sys/fs/cgroup/unified and
# cgroups version 1 on /sys/fs/cgroup.
# "legacy" mounts cgroups version 1 on /sys/fs/cgroup
# "unified" mounts cgroups version 2 on /sys/fs/cgroup
rc_cgroup_mode="unified"
# This is a list of controllers which should be enabled for cgroups version 2.
# If hybrid mode is being used, controllers listed here will not be
# available for cgroups version 1.
# This is a global setting.
rc_cgroup_controllers="systemd"
...
...
...
Older versions up to lxd-3.9 might need a raw.lxc config entry in addition to mount the host's cgroups automagically into the container:
user $lxc config set <container> raw.lxc 'lxc.mount.auto = cgroup'For more details take a look a the upstream issue on github.com
Alternative way (lxd-4.0.9)
Modify these parts, as instructed above:
/etc/rc.confrc_cgroup_mode="hybrid"
rc_cgroup_controllers="yes"
rc_controller_cgroups="yes"
After that create /etc/init.d/cgroups-systemd init-file with following content:
/etc/init.d/cgroups-systemd#!/sbin/openrc-run
# Copyright 2022 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
description="Mount the control groups (systemd)."
cgroup_opts=nodev,noexec,nosuid
depend() {
after cgroups
}
start() {
mkdir -p /sys/fs/cgroup/systemd
mount -n -t cgroup -o none,${cgroup_opts},name=systemd systemd /sys/fs/cgroup/systemd
}
Add created init-file into sysvinit runlevel:
root #rc-update add cgroups-systemd sysvinit
root #rc-service start cgroups-systemd
user $lxc launch images:fedora/36 fedora-systemd-img
user $lxc stop fedora-systemd-img
user $lxc config set fedora-systemd-img limits.cpu 6
user $lxc config set fedora-systemd-img limits.memory 8GB
user $lxc start fedora-systemd-img
user $lxc exec fedora-systemd-img bashUsing LXD with self-spun ZFS pools
If you use ZFS with LXD and provide it the full pool path, then LXD will export the pool on shutdown for safety.
On startup, LXD will look for pools in a standard path, /var/lib/lxd/disks/ and in the block devices (which can be displayed using /bin/lsblk.
If you create your own pools outside of LXD and those are not in the standard path or in block devices, you must import them explicitly before starting LXD if you want LXD to find them. If you do not, LXD will fail to start.
(See https://discuss.linuxcontainers.org/t/lxd-exports-zfs-pools-at-shutdown-but-does-not-import-them-properly-at-startup/13031/2 for more information.)
Too many open files on OpenRC hosts
If an error due to Too many open files is encountered when the daemon is started via OpenRC, increase the limit by setting the rc_ulimit variable in /etc/conf.d/lxd:
/etc/conf.d/lxdRecommended production values...
rc_ulimit="-n 1048576 -l unlimited"
...
Since OpenRC doesn't use PAM, /etc/etc/security/limits.conf will be ignored.
See also
- LXC — a virtualization system making use of Linux's namespaces and cgroups.
- Podman — a daemonless container engine for developing, managing, and running OCI Containers on Linux.
- docker — a container virtualization environment
External Resources
- LXC and LXD: a different container story
- LXD upstream's discussion site, support forums etc.
- LXD upstream's official Youtube channel.
- Just me and Opensource Youtube channel, multiple LXD related guide videos. Better filtering.
- User:Juippis/The_ultimate_testing_system_with_lxd A real life Gentoo usage example.
- ↑ LXD Introduction, Linux Containers. Retreived on March 12th, 2021.