Provide an alternative way to retrieve available public ips from a subnet

[julien-jean]

Hello there !

I've been lurking about the issue about getting the first free available ip address from phpipam (phpipam/phpipam#2960) and I was wondering if there were some alternative solution.

Basically, I'd like to implement a new datasource, let's say subnet_free_addresses and would expose the available IP addresses by the following process:

1. fetch a given subnet as CIDR format
2. cast the CIDR address as a list of IP addresses
3. fetch the list of addresses of the given subnet
4. remove all used address from the list computed in step 2

Having a PHPIPAM endpoint that would retrieve a subnet available ips would drastically simplify that process as it would remove all CIDR computations.

Once that data source would be available, we could write our modules like so :

data "phpipam_subnet_free_addresses" "free_addresses" {
  subnet_id = 12
}

resource "vmware_vm" "my_vms" {
  count = 3
  // .... //
  ipv4_addr = data.phpipam_subnet_free_addresses.free_addresses[count.index].ipv4_addr
}

It feels to me like it is a good alternative to the first_free_address endpoint usage which does not work in our case. What do you think about it ?

If the solution seems convenient to you, I'd like to suggest a pull request that would implement such solution.

Bye !

[julien-jean]

I ended up with something like this seems fully functional. I'm quite new to phpipam so I don't know if there are some edge cases where it won't work but it fits our internal needs for now.

Let's say I need to get 10 free IP addresses :

data "phpipam_subnet" "my_subnet" {
  subnet_address = "192.168.1.0"
  subnet_mask    = 24
}

# this new data source retrieves the nth free addresses of a subnet 
# and fails if there is not enough available addresses
data "phpipam_nth_free_addresses" "ten_addresses" {
  number    = 10
  subnet_id = data.phpipam_subnet.my_subnet.subnet_id
}

output "some_free_addresses" {
  value = data.phpipam_nth_free_addresses.ten_addresses
}

# reuse the ten_addresses source the way you want when spinning VMs 
# don't forget to use the `phpipam_address` resource for each IP address !

I ended by adding a number property because retrieving all the free ip addresses of a subnet can be quite complex and irrelevant (thus I guess that anyone should be able to compute the number of desired IPs).

I'm cleaning my work then I'll create a pull request !

[pavel-z1]

Hi @julien-jean

The task with multiple IPs has been a long time ago for me.
I can't remember all the nuances of the phpipam problem with receiving free_address in loop.

In my case, previously, I needed to get the last IP address in a loop from different subnets, not from the same subnet.
I was able to solve this with terraforms using loops and explicit use of subnet data source indexes.
I don't think my code would be readable here.

Feel free to create your Pull Request. Maybe new feature will be useful to other users of this terraform provider.

[lord-kyron]

@julien-jean Will you provide some pull request about this issue or I can close this ?

[lord-kyron]

Closed because of inactivity