IPv6 instance group backend showing as unhealthy

mountaincode2 · 04-02-2025 05:58 AM

I am following the guidance in:

https://cloud.google.com/load-balancing/docs/internal/setting-up-internal#configure-ipv6-only

I am creating an internal passthrough network load balancer with IPv6 only subnets and backends. I have created the firewall to allow checks from source IPv6 ranges: 2600:2d00:1:b029::/64

Why is my IPv6 instance group showing as unhealthy:

mountaincode2

Update:

I see that there is no webserver running on the vms:

sudo systemctl status apache2

Unit apache2.service could not be found.

could it be the reason that health check is failing.

In the following it says that:

Each VM is assigned an internal IP address in the lb-subnet-ipv6-only and an ephemeral external (public) IP address. You can remove the external IP addresses later.

But i don't see any external IP address allocated:

https://cloud.google.com/load-balancing/docs/internal/setting-up-internal#configure_instance_groups_...

DarwinVinoth

@mountaincode2 Did you configure any health check profile for the Instance Group?

mountaincode2

Hi @DarwinVinoth

Yes, i have created a health check:

gcloud beta compute health-checks create http hc-http-80 \
    --region=us-west1 \
    --port=80

kensan

Hi @mountaincode2 ,

Welcome to Google Cloud Community!

Creating a VM instance with a single stack IPv6 will automatically allocate the external IP. This will permit the backend VMs to download Apache from the internet, and you can connect to them using SSH.

Ensure that server software running on your backend VMs is actively waiting for incoming connections directed to the IP address IP address of the load balancer's internal forwarding rule.

Was this helpful? If so, please accept this answer as “Solution”. If you need additional assistance, reply here within 2 business days and I’ll be happy to help.

mountaincode2

@kensan

I cannot see the "External IPv6 address" dropdown in the "Create a VPC network" page.

When i select IP stack type as IPv6, all i see is the IPv6 access type dropdown.

What do i need to do.

kensan

Hi @mountaincode2,

Assigning External IP is not on creating VPC network. You can check Compute Engine>VM instance>create instance *select the region where your IPv6 subnet is located* >networking>network interfaces.

network - select your IPv6 subnet vpc

IP stack - select IPv6(single Stack)

External IPv6 address - Auto-Allocate

mountaincode2

@kensan

Hi, again i don't see the option to allocate an external IPv6 address even in the VM instance creation page:

mountaincode2

Can someone please help me with this.

Thank you!

mountaincode2

Creating another network interface on the VM with an IPv4 address also doesn’t install the startup script: