Create LXC Templates

Create LXC Templates

Every time inspiration struck or I saw a blog post with something I wanted to try, it was frustrating and time consuming to get the base operating system set up to the way I like it before proceeding with the project.

Now I just update the template each point release or when I add something substantial to my dotfiles so it's ready to go whenever I need to spin up a fresh container.

It only takes a few minutes to set up or modify and can save lots of time in the long run.

Select an Image

SSH into Proxmox:
```
ssh proxmox
```
List available system images (change sas-storage to wherever they are stored on your system eg. local):
```
sudo pveam list sas-storage
```
- If what we want isn't there, update container template database:
```
sudo pveam update
```
- List available images:
```
sudo pveam available
```
- You can also filter the output:
```
sudo pveam available --section system
```

Download the image:

sudo pveam download sas-storage debian-10.0-standard_10.0-1_amd64.tar.gz

See man pveam for more details.

Create the Container

Now we need to create the container that we will be updating and adding our programs to. Note that you will need to modify the following command to match your system.

Create a container:

sudo pct create 250 sas-storage:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz \
  --storage sas-lvm --rootfs volume=sas-lvm:16 \
  --ostype debian --arch amd64 --password insecure --unprivileged 1 \
  --cores 1 --memory 1024 --swap 1024 \
  --hostname lxc-template --searchdomain local.lan --nameserver xxx.xxx.xxx.x \
  --net0 name=eth0,bridge=vmbrxx,ip=dhcp,gw=xxx.xxx.xx.x,type=veth \
  --start true

See man pct for more information.

Modify the Container

Here's where we update/add programs/configure it to our liking.

Enter the container:
```
sudo pct enter 250
```
Do stuff:
- Update the system:
```
apt update && apt upgrade
```
- Install some packages:
```
apt install curl git screen stow unattended-upgrades vim
```
- Set Vim as default editor:
```
update-alternatives --set editor /usr/bin/vim.basic
```
- Create user:
```
adduser user
```
- Switch to user:
```
su - user
```
- Clone dotfiles:
```
git clone https://path.to/dotfiles ~/.dotfiles
```
- Stow the dotfiles:
```
stow dotfiles
```
- Create ~/.ssh directory:
```
mkdir ~/.ssh
```
- Create ~/.ssh/authorized_keys file with your pubkey
- And so on….
- Bonus points if you have an Ansible playbook to run the commands!

Create the template

In order to turn the container into a template, we need to delete the network interface then create a backup.

From proxmox (not inside the container):
Remove the network interface:
```
sudo pct set 250 --delete net0
```

Create a backup:

vzdump 250 --mode stop --compress gzip --dumpdir /media/sas/data/template/cache/

The new file will be located in:
```
/media/sas/data/template/cache
```

You can leave it as is or rename it to something:

Change directories:
```
cd /media/sas/data/template/cache
```

Rename it:

sudo mv new_vz_dump.tar.gz custom_debian_10.4.tar.gz

See man vzdump for info.

Cleaning up

Feel free to delete the container we used to make the template (250).

Modifying or Updating

It's really easy to modify the container when a new version of the OS is released or you want to add something to your templates.

Create a container with your custom file:

sudo pct create 250 sas-storage:vztmpl/custom_debian_10.4.tar.gz \
  --storage sas-lvm --rootfs volume=sas-lvm:16 \
  --ostype debian --arch amd64 --password insecure --unprivileged 1 \
  --cores 1 --memory 1024 --swap 1024 \
  --hostname lxc-template --searchdomain local.lan --nameserver xxx.xxx.xxx.x \
  --net0 name=eth0,bridge=vmbrxx,ip=dhcp,gw=xxx.xxx.xxx.x,type=veth \
  --start true

Enter the container:
```
sudo pct enter 250
```
Do stuff:
- Update the system:
```
apt update && apt upgrade
```
- Install some packages
- Add new dotfiles
- And so on..
Exit back to Proxmox:
```
exit
```
Remove the network device:
```
sudo pct set 250 --delete net0
```

Create the backup:

vzdump 250 --mode stop --compress gzip --dumpdir /media/sas/data/template/cache/