Find free IP inside a vnet/subnet

[calinmarina]

Is your feature request related to a problem? Please describe.
It is very often when you need to find a free IP to further use it, for example to create a load balancer:

az network lb create \
    --resource-group $RgName \
    --name $LoadBalancerName \
    --frontend-ip-name $FrontEndName \
    --private-ip-address $privateIPAddress \
    --backend-pool-name $BackEndPool \
    --vnet-name $vnetName \
    --subnet $SubNet 

Q: is there something in the CLI that helps with that?

Describe the solution you'd like
I'd like to have something off the shelf like:
az network vnet --get-private-ip-address
... so we don't have to iterate through the whole vnet and check for a free one

[yugangw-msft]

One option is you can dump out used private ip addresses in a vnet using a command below and then pick a free one you can use. Will that help?

az network nic list --query "[?starts_with(ipConfigurations[0].subnet.id,`/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272xxxxx/resourceGroups/myGroup/providers/Microsoft.Network/virtualNetworks/myVnet/subnets/subnet`)]|[].ipConfigurations[0].privateIpAddress" -otsv
10.0.0.4
10.0.0.5
10.0.0.6

[calinmarina]

might do... I did discover meanwhile that knowing any IP in the subnet (I had a VM in there) you can check if it is available and you will get false but also a list of free IPs in the subnet:
privateIPAddress="$(az network vnet check-ip-address --resource-group $RgName --name $vnetName --ip-address $known_ip | jq -r .availableIpAddresses[0])"

[yugangw-msft]

Good find! This is a better option :)

[adewaleo]

It seems this issue has been resolved?

i will be closing this issue. If you have any further questions, please let us know.

[calinmarina]

well... it's a feature request, it hasn't been resolved or implemented, we rather found something to help not even a workaround, so I wouldn't leave it closed as it's not

... at the moment Closed means rejected

[yugangw-msft]

@christiankuhtz(from network team) could please chime in whether or not this is a common user ask. If yes, we can reactivate as a feature work which @adewaleo will happily implement

[adewaleo]

@calinmarina, thanks for following up. My apologies if we misunderstood you. I would be happy to implement this feature if the network team / @yugangw-msft gives the go-ahead.

[a-dimas]

@calinmarina, thanks for following up. My apologies if we misunderstood you. I would be happy to implement this feature if the network team / @yugangw-msft gives the go-ahead.

Have they given it?

[calinmarina]

Not as far as I know... it's at the phase where you need to vote for it :)
👍 if you need it