How did I use LXD to manage dev environment?
I've used LXD for a while when I worked for Canonical, it's really cool thing to create the isolated linux development environments.
What is LXD?
The main feature of LXD is that it provides the virtual machines similar functions by using and managing the linux containers. it's much lighter and faster than the traditional virtual machines.
It's image based with a bunch of pre-made images.
You can find more details from [official site] (https://linuxcontainers.org/lxd/introduction/)
Installtion
Ubuntu:
apt install lxd lxd-client
or
snap install lxd
Mac:
brew install lxc
Create the ZFS pool
What is ZFS
ZFS(Zettabyte File System) can provide the intelligent performance and data integrity when given a pool of disks. ZFS has some outstanding features:
- ZFS is 128-bit, so it's super scalable. So the following data storage units, in theory it can store up to 2 ** (128 - 80) Yib data.
Data storage units measurement
1Kib = 2 ** 10 (Kilobyte)
1Mib = 2 ** 20 (Megabyte)
1Gib = 2 ** 30 (Gigabyte)
1Tib = 2 ** 40 (Tebibyte)
1Pib = 2 ** 50 (Pebibye)
1Eib = 2 ** 60 (Exbibyte)
1Zib = 2 ** 70 (Zettabyte)
1Yib = 2 ** 80 (Yobibyte)
Since ZFS uses a storage pool, it means the storage can be dynamically added to ore removed from the pools without interrupting services.
-
Unsurpassed data reliability
By transparently checking the checksums in parent block pointers, the data reliablity is ensured. it includes the silent corruption detection and automatic data repair. -
Provide the compression to reduce the disk space and IO bandwidth
See more details from here
Create the ZFS pool
On ubuntu, install the package:
$ sudo apt install zfsutils-linux
then using the zpool to creat the storage pool:
-
A partion/disk based zpool
$ sudo zpool create lxd-pool /dev/mapper/vg_ubuntu-lv_zfs
$ sudo zpool status
pool: lxd
state: ONLINE
scan: none requested
config:NAME STATE READ WRITE CKSUM lxd ONLINE 0 0 0 vg_ubuntu-lv_zfs ONLINE 0 0 0 -
A partion/disk based zpool
$ dd if=/dev/zero of=/home/user/image-file-name bs=1M count=2048
$ sudo zpool create lxd-pool /home/user/image-file-name
$ sudo zpool status
pool: lxd-pool
state: ONLINE
scan: none requested
config:NAME STATE READ WRITE CKSUM lxd-pool ONLINE 0 0 0 /home/user/image-file-name ONLINE 0 0 0
For more ZFS operations see here
Create the lxc instance
Now you can create your instance simply run:
$ lxc launch ubuntu:18.04 dev-env
First time it takes some time to download the ubuntu 18.04 images.
see the lxc container list:
$ lxc list
access the container shell:
$ lxc exec dev-env -- /bin/bash
push a file to container:
lxc file push hosts/file dev-env/tmp/
stop the container:
$ lxc stop dev-env
start the container:
$ lxc start dev-env
Now you can see it's dramatically quickly start and stop the containers.
finally you can delete the container:
$ lxc delete dev-env
Be sure the container is stopped before you delete the container
Create the Development Profile
When we use the LXC instance as our development environment, we don want to share the project folder or home folder from the host machine, we can define the disk, network policy from the profile:
First we create a new profile:
$ lxc profile create my-dev-profile
$ lxc profile edit my-dev-profile
then replace the following snippet in the editor:
config:
security.privileged: "true"
user.user-data: |
users:
name: user_name
groups: sudo
shell: /bin/bash
description: dev profile for lxd
devices:
.home:
path: /home/user_name
source: /home/user_name
type: disk
eth0:
name: eth0
nictype: bridged
parent: lxdbr0
type: nic
root:
path: /
pool: lxd-pool # Remember to use the above new created pool name here
type: disk
A useful script to auto create the LXC instance
Restore the LXC containers
sudo zpool create -m /dev/sda13 lxd
sudo zpool attach lxd /dev/sda13
sudo zpool attach /dev/sda13 lxd
sudo zpool reopen lxd
sudo zpool create lxd /dev/sda13
sudo zpool create lxd /dev/sda13 -f