Network configuration using netplan for Ubuntu versions greater than 16.04

[gauravgahlot]

Signed-off-by: Gaurav Gahlot [email protected]

[grahamc]

What would you think about moving the netplan-specific code in to two helper functions:

1. is_netplan
2. setup_networking_netplan

the setup_networking function is quite large, and I'm a bit afraid of letting it grow too much more.

[grahamc]

Generating YAML on the fly with bash feels a bit scary. In particular, magic values can turn in to other things like "no" being a bool, and 1.10 being just 1.1. What would you think about using (and installing if it isn't yet available) jq for this? Using jq guarantees the output will be correct and that we didn't make an error in indentation, whitespace, and also makes sure that all of the values are properly quoted.

Here is an example of what that would look like:

TINKERBELL_NETWORK_INTERFACE=10.5.3.1
TINKERBELL_HOST_IP=10.5.3.2
TINKERBELL_NGINX_IP=10.5.3.3
cidr=24

jq -n \
   --arg interface "$TINKERBELL_NETWORK_INTERFACE" \
   --arg cidr "$cidr" \
   --arg host_ip "$TINKERBELL_HOST_IP" \
   --arg nginx_ip "$TINKERBELL_NGINX_IP" \
   '{
  network: "hi",
  renderer: "networkd",
  ethernets: {
    ($interface): {
      addresses: [
        "\($host_ip)/\($cidr)",
        "\($nginx_ip)/\($cidr)"
      ]
    }
  }
}'

This prints:

{
  "network": "hi",
  "renderer": "networkd",
  "ethernets": {
    "10.5.3.1": {
      "addresses": [
        "10.5.3.2/24",
        "10.5.3.3/24"
      ]
    }
  }
}

since JSON is valid YAML, this output works directly with netplan.

[grahamc]

It looks like 17.10 is the first release to use netplan by default. Maybe we should change this to >= 17.10?

[grahamc]

I wonder if netplan creates a systemd unit we could wait for, like this:

while ! systemctl is-active netplan-something-or-other; do
  sleep 1
done

[grahamc]

Oops, I meant to also say -- looks pretty good!

[grahamc]

These commits were included in #147