The Funtoo Linux project has transitioned to "Hobby Mode" and this wiki is now read-only.
Difference between revisions of "LXD"
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* dnsmasq listening on lxdbr0 | * dnsmasq listening on lxdbr0 | ||
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== | == Containers, snapshots and images == | ||
'''Containers''' in LXD are made of: | |||
* A filesystem (rootfs) | |||
* A list of configuration options, including resource limits, environment, security options and more | |||
* A bunch of devices like disks, character/block unix devices and network interfaces | |||
* A set of profiles the container inherits configuration from (see below) | |||
* Some properties (container architecture, ephemeral or persistent and the name) | |||
* Some runtime state (when using CRIU for checkpoint/restore) | |||
Container '''snapshots''' as the name states snapshots of the container in time and cannot be modified in any way. It is worth noting that because snapshots can store the container runtime state, which gives us ability of “stateful” snapshots. That is, the ability to rollback the container including its cpu and memory state at the time of the snapshot. | |||
LXD is '''image''' based, all LXD containers come from an image. Images are typically clean Linux distribution images similar to what you would use for a virtual machine or cloud instance. It is possible to “publish” a container, making an image from it which can then be used by the local or remote LXD hosts. | |||
Revision as of 19:55, September 6, 2017
LXD is a container "hypervisor" it should provide user with a new and fresh experience using LXC technology.
LXD consists of three components:
- A system-wide daemon (lxd)
- A command line client (lxc)
- An OpenStack Nova plugin (nova-compute-lxd)
A REST API that is accesible both locally and if enabled, over the network is provided from the lxd daemon.
The command line tool is designed to be a very simple, yet very powerful tool to manage all your containers. It can handle connections to multiple container hosts and easily give you an overview of all the containers on your network, let you create some more where you want them and even move them around while they're running.
The OpenStack plugin then allows you to use your lxd hosts as compute nodes, running workloads on containers rather than virtual machines.
The LXD project was founded and is currently led by Canonical Ltd and Ubuntu with contributions from a range of other companies and individual contributors.
Features
Some of the biggest features of LXD are:
- Secure by design (unprivileged containers, resource restrictions and much more)
- Scalable (from containers on your laptop to thousand of compute nodes)
- Intuitive (simple, clear API and crisp command line experience)
- Image based (no more distribution templates, only good, trusted images)
- Live migration
Relationship with LXC
LXD isn't a rewrite of LXC, in fact it's building 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.
Licensing
LXD is free software and is developed under the Apache 2 license.
Installing LXD in Funtoo
Kernel pre-requisities
These options should be enable in your kernel to use all of the functions of LXD:
!GRKERNSEC_CHROOT_CAPS
!GRKERNSEC_CHROOT_CHMOD
!GRKERNSEC_CHROOT_DOUBLE
!GRKERNSEC_CHROOT_MOUNT
!GRKERNSEC_CHROOT_PIVOT
!GRKERNSEC_PROC
!GRKERNSEC_SYSFS_RESTRICT
!NETPRIO_CGROUP
BRIDGE
CGROUP_CPUACCT
CGROUP_DEVICE
CGROUP_FREEZER
CGROUP_SCHED
CGROUPS
CHECKPOINT_RESTORE
CPUSETS
DEVPTS_MULTIPLE_INSTANCES
DUMMY
EPOLL
EVENTFD
FHANDLE
IA32_EMULATION
INET_DIAG
INET_TCP_DIAG
INET_UDP_DIAG
INOTIFY_USER
IP_NF_NAT
IP_NF_TARGET_MASQUERADE
IP6_NF_NAT
IP6_NF_TARGET_MASQUERADE
IPC_NS
IPV6
MACVLAN
NAMESPACES
NET_IPGRE
NET_IPGRE_DEMUX
NET_IPIP
NET_NS
NETFILTER_XT_MATCH_COMMENT
NETLINK_DIAG
NF_NAT_MASQUERADE_IPV4
NF_NAT_MASQUERADE_IPV6
PACKET_DIAG
PID_NS
POSIX_MQUEUE
UNIX_DIAG
USER_NS
UTS_NS
VETH
VXLAN
Getting LXD
Installing LXD is pretty straight forward as the ebuild exists in our portage tree. I would recommend putting /var on btrfs or zfs (or at least /var/lib/lxd) as LXD can take advantage of these COW filesytems.
root # emerge -av lxd These are the packages that would be merged, in order: Calculating dependencies... done! [ebuild N ] dev-lang/go-1.8-r1:0/1.8::gentoo USE="-gccgo" 69,062 KiB [ebuild N ] dev-go/go-crypto-0_pre20160126:0/0_pre20160126::gentoo 881 KiB [ebuild N ] sys-fs/squashfs-tools-4.3-r2::gentoo USE="xattr xz -debug -lz4 -lzma -lzo -static" 194 KiB [ebuild N ] sys-libs/libseccomp-2.3.2::gentoo USE="-static-libs" 547 KiB [ebuild N ] net-libs/libnet-1.2_rc3-r1:1.1::gentoo USE="-doc -static-libs" 661 KiB [ebuild N ] dev-libs/libnl-3.3.0_rc1:3::gentoo USE="python -static-libs -utils" PYTHON_TARGETS="python2_7 python3_4 -python3_5" 912 KiB [ebuild N ] dev-python/ipaddr-2.1.11-r1::gentoo PYTHON_TARGETS="python2_7 python3_4 -pypy -python3_5" 29 KiB [ebuild N ] dev-go/go-text-0_pre20160211:0/0_pre20160211::gentoo 3,922 KiB [ebuild N ] sys-libs/libcap-2.25::gentoo USE="pam -static-libs" 63 KiB [ebuild N ] dev-go/go-net-0_pre20160216:0/0_pre20160216::gentoo 724 KiB [ebuild N ] net-dns/dnsmasq-2.76-r1::gentoo USE="dhcp inotify ipv6 nls -auth-dns -conntrack -dbus -dhcp-tools -dnssec -idn -lua -script (-selinux) -static -tftp" LINGUAS="-de -es -fi -fr -id -it -no -pl -pt_BR -ro" 470 KiB [ebuild N ] dev-libs/protobuf-c-1.2.1-r1:0/1.0.0::gentoo USE="-static-libs {-test}" 448 KiB [ebuild N ] sys-process/criu-2.12::gentoo USE="python -setproctitle" PYTHON_TARGETS="python2_7" 632 KiB [ebuild N ] app-emulation/lxc-2.0.7::gentoo USE="python seccomp -cgmanager -doc -examples -lua" PYTHON_TARGETS="python3_4 -python3_5" 774 KiB [ebuild N ] app-emulation/lxd-2.11::gentoo USE="daemon nls {-test}" LINGUAS="-de -el -fr -ja -nl -ru" 2,352 KiB Total: 15 packages (15 new), Size of downloads: 81,664 KiB Would you like to add these changes to your config files? [Yes/No]
Running LXD
Once installed you need to start the LXD daemon. By running:
root # service lxd start * Starting lxd server ...
First setup of LXD/Initialisation
Before using LXD for the first time as a user, you may initialize your LXD environment. As recommended earlier I am using btrfs for this installation.
user $ lxd init 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, btrfs, lvm) [default=dir]: btrfs Create a new BTRFS pool (yes/no) [default=yes]? Would you like to use an existing block device (yes/no) [default=no]? Would you like to create a new subvolume for the BTRFS storage pool (yes/no) [default=yes]: 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 to create a new network bridge (yes/no) [default=yes]? What should the new bridge be called [default=lxdbr0]? What IPv4 address should be used (CIDR subnet notation, “auto” or “none”) [default=auto]? What IPv6 address should be used (CIDR subnet notation, “auto” or “none”) [default=auto]? LXD has been successfully configured.
What this does is it creates btrfs subvolumes like this:
user $ btrfs sub list . ID 260 gen 1047 top level 5 path rootfs ID 280 gen 1046 top level 260 path var/lib/lxd/storage-pools/default ID 281 gen 1043 top level 280 path var/lib/lxd/storage-pools/default/containers ID 282 gen 1044 top level 280 path var/lib/lxd/storage-pools/default/snapshots ID 283 gen 1045 top level 280 path var/lib/lxd/storage-pools/default/images ID 284 gen 1046 top level 280 path var/lib/lxd/storage-pools/default/custom
It also creates new network interface for you:
user $ ip a list dev lxdbr0 8: lxdbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000 link/ether d2:9b:70:f2:8f:6f brd ff:ff:ff:ff:ff:ff inet 10.250.237.1/24 scope global lxdbr0 valid_lft forever preferred_lft forever inet 169.254.59.23/16 brd 169.254.255.255 scope global lxdbr0 valid_lft forever preferred_lft forever inet6 fd42:efd8:662e:3184::1/64 scope global valid_lft forever preferred_lft forever inet6 fe80::caf5:b7ed:445e:b112/64 scope link valid_lft forever preferred_lft forever
And last but not least it also generates iptables rules for you:
user $ iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT tcp -- anywhere anywhere tcp dpt:domain /* generated for LXD network lxdbr0 */ ACCEPT udp -- anywhere anywhere udp dpt:domain /* generated for LXD network lxdbr0 */ ACCEPT udp -- anywhere anywhere udp dpt:bootps /* generated for LXD network lxdbr0 */ Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere /* generated for LXD network lxdbr0 */ ACCEPT all -- anywhere anywhere /* generated for LXD network lxdbr0 */ Chain OUTPUT (policy ACCEPT) target prot opt source destination ACCEPT tcp -- anywhere anywhere tcp spt:domain /* generated for LXD network lxdbr0 */ ACCEPT udp -- anywhere anywhere udp spt:domain /* generated for LXD network lxdbr0 */ ACCEPT udp -- anywhere anywhere udp spt:bootps /* generated for LXD network lxdbr0 */ user $ iptables -L -t nat Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain INPUT (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination MASQUERADE all -- 10.250.237.0/24 !10.250.237.0/24 /* generated for LXD network lxdbr0 */ user $ iptables -L -t mangle Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination CHECKSUM udp -- anywhere anywhere udp dpt:bootpc /* generated for LXD network lxdbr0 */ CHECKSUM fill
Some other things done by the initialization and starting of the LXD daemon are:
- dnsmasq listening on lxdbr0
Containers, snapshots and images
Containers in LXD are made of:
- A filesystem (rootfs)
- A list of configuration options, including resource limits, environment, security options and more
- A bunch of devices like disks, character/block unix devices and network interfaces
- A set of profiles the container inherits configuration from (see below)
- Some properties (container architecture, ephemeral or persistent and the name)
- Some runtime state (when using CRIU for checkpoint/restore)
Container snapshots as the name states snapshots of the container in time and cannot be modified in any way. It is worth noting that because snapshots can store the container runtime state, which gives us ability of “stateful” snapshots. That is, the ability to rollback the container including its cpu and memory state at the time of the snapshot.
LXD is image based, all LXD containers come from an image. Images are typically clean Linux distribution images similar to what you would use for a virtual machine or cloud instance. It is possible to “publish” a container, making an image from it which can then be used by the local or remote LXD hosts.