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Proxy Setup Instructions

This doc covers procedures to configure, build and deploy the Netty-based proxy onto Kubernetes clusters. Google Kubernetes Engine is used as deployment target. Any kubernetes cluster should in theory work, but the user needs to change some dependencies on other GCP features such as Cloud KMS for key management and Stackdriver for monitoring.


Nomulus runs on Google App Engine, which only supports HTTP(S) traffic. In order to work with EPP (TCP port 700) and WHOIS (TCP port 43), a proxy is needed to relay traffic between clients and Nomulus and do protocol translation.

We provide a Netty-based proxy that runs as a standalone service (separate from Nomulus) either on a VM or Kubernetes clusters. Deploying to kubernetes is recommended as it provides automatic scaling and management for docker containers that alleviates much of the pain of running a production service.

The procedure described here can be used to set up a production environment, as most of the steps only needs to be configured once for each environment. However, proper release management (cutting a release, rolling updates, canary analysis, reliable rollback, etc) is not covered. The user is advised to use a service like Spinnaker for release management.

Detailed Instruction

We use gcloud and terraform to configure the proxy project on GCP. We use kubectl to deploy the proxy to the project. Additionally, gsutil is used to create GCS bucket for storing the terraform state file. These instructions assume that all four tools are installed.

Setup GCP project

There are three projects involved:

  • Nomulus project: the project that hosts Nomulus.
  • Proxy project: the project that hosts this proxy.
  • GCR (Google Container Registry) project: the project from which the proxy pulls its Docker image.

We recommend using the same project for Nomulus and the proxy, so that logs for both are collected in the same place and easily accessible. If there are multiple Nomulus projects (environments), such as production, sandbox, alpha, etc, it is recommended to use just one as the GCR project. This way the same proxy images are deployed to each environment, and what is running in production is the same image tested in sandbox before.

The following document outlines the procedure to setup the proxy for one environment.

In the proxy project, create a GCS bucket to store the terraform state file:

$ gsutil config # only if you haven't run gsutil before.
$ gsutil mb -p <proxy-project> gs://<bucket-name>/

Obtain a domain and SSL certificate

The proxy exposes two endpoints, whois.<yourdomain.tld> and epp.<yourdomain.tld>. The base domain <yourdomain.tld> needs to be obtained from a registrar (Google Domains for example). Nomulus operators can also self-allocate a domain in the TLDs under management.

EPP protocol over TCP requires a client-authenticated SSL connection. The operator of the proxy needs to obtain an SSL certificate for domain epp.<yourdomain.tld>. Let's Encrypt offers SSL certificate free of charge, but any other CA can fill the role.

Concatenate the certificate and its private key into one file:

$ cat <certificate.pem> <private.key> > <combined_secret.pem>

The order between the certificate and the private key inside the combined file does not matter. However, if the certificate file is chained, i. e. it contains not only the certificate for your domain, but also certificates from intermediate CAs, these certificates must appear in order. The previous certificate's issuer must be the next certificate's subject.

The certificate will be encrypted by KMS and uploaded to a GCS bucket. The bucket will be created automatically by terraform.

Setup proxy project

First setup the Application Default Credential locally:

$ gcloud auth application-default login

Login with the account that has "Project Owner" role of all three projects mentioned above.

Navigate to proxy/terraform, create a folder called envs, and inside it, create a folder for the environment that proxy is deployed to ("alpha" for example). Copy to the environment folder.

$ cd proxy/terraform
$ mkdir -p envs/alpha
$ cp envs/alpha/

Now go to the environment folder, edit the file and replace placeholders with actual project and domain names.

Run terraform:

$ cd envs/alpha
$ terraform init -upgrade
$ terraform apply

Go over the proposed changes, and answer "yes". Terraform will start configuring the projects, including setting up clusters, keyrings, load balancer, etc. This takes a couple of minutes.

Setup Nomulus

After terraform completes, it outputs some information, among which is the client id of the service account created for the proxy. This needs to be added to the Nomulus configuration file so that Nomulus accepts traffic from the proxy. Edit the following section in java/google/registry/config/files/nomulus-config-<env>.yaml and redeploy Nomulus:

    - <client_id>

Setup nameservers

The terraform output (run terraform output in the environment folder to show it again) also shows the nameservers of the proxy domain (<yourdomain.tld>). Delegate this domain to these nameservers (through your registrar). If the domain is self-allocated by Nomulus, run:

$ nomulus -e production update_domain <yourdomain.tld> \
-c <registrar_client_name> -n <nameserver1>,<nameserver2>,...

Setup named ports

Unfortunately, terraform currently cannot add named ports on the instance groups of the GKE clusters it manages. Named ports are needed for the load balancer it sets up to route traffic to the proxy. To set named ports, in the environment folder, do:

$ bash ../../

Encrypt the certificate to Cloud KMS

With the newly set up Cloud KMS key, encrypt the certificate/key combo file created earlier:

$ gcloud kms encrypt --plaintext-file <combined_secret.pem> \
--ciphertext-file - --key <key-name> --keyring <keyring-name> --location \
global | base64 > <combined_secret.pem.enc>

This encrypted file is then uploaded to a GCS bucket specified in the file.

$ gsutil cp <combined_secret.pem.enc> gs://<your-certificate-bucket>

Edit proxy config file

Proxy configuration files are at java/google/registry/proxy/config/. There is a default config that provides most values needed to run the proxy, and several environment-specific configs for proxy instances that communicate to different Nomulus environments. The values specified in the environment-specific file override those in the default file.

The values that need to be changed include the project name, the Nomulus endpoint, encrypted certificate/key combo filename and the GCS bucket it is stored in, Cloud KMS keyring and key names, etc. Refer to the default file for detailed descriptions on each field.

Upload proxy docker image to GCR

Edit the proxy_push rule in java/google/registry/proxy/BUILD to add the GCR project name and the image name to save to. Note that as currently set up, all images pushed to GCR will be tagged bazel and the GKE deployment object loads the image tagged as bazel. This is fine for testing, but for production one should give images unique tags (also configured in the proxy_push rule).

To push to GCR, run:

$ bazel run java/google/registry/proxy:proxy_push

Deploy proxy

Terraform by default creates three clusters, in the Americas, EMEA, and APAC, respectively. We will have to deploy to each cluster separately. The cluster information is shown by terraform output as well.

Deployment is defined in two files, proxy-deployment-<env>.yaml and proxy-service.yaml. Edit proxy-deployment-<env>.yaml for your environment, fill in the GCR project name and image name. You can also change the arguments in the file to turn on logging, for example. To deploy to a cluster:

# Get credentials to deploy to a cluster.
$ gcloud container clusters get-credentials --project <proxy-project> \
--zone <cluster-zone> <cluster-name>

# Deploys environment specific kubernetes objects.
$ kubectl create -f \

# Deploys shared kubernetes objects.
$ kubectl create -f \

Repeat this for all three clusters.


Remember to turn on Stackdriver Monitoring for the proxy project as we use it to collect metrics from the proxy.

You are done! The proxy should be running now. You should store the private key safely, or delete it as you now have the encrypted file shipped with the proxy. See "Additional Steps" in the appendix for other things to check.


Here we give detailed instructions on how to configure a GCP project to host the proxy manually. We strongly recommend against doing so because it is tedious and error-prone. Using Terraform is much easier. The following instructions are for educational purpose for readers to understand why we set up the infrastructure this way. The Terraform config is essentially a translation of the following procedure.

Set default project

The proxy can run on its own GCP project, or use the existing project that also hosts Nomulus. We recommend initializing the gcloud config to use that project as default, as it avoids having to provide the --project flag for every gcloud command:

$ gcloud init

Follow the prompt and choose the project you want to deploy the proxy to. You can skip picking default region and zones, as we will explicitly create clusters in multiple zones to provide geographical redundancy.

Create service account

The proxy will run with the credential of a service account. In theory it can take advantage of Application Default Credentials and use the service account that the GCE instance underpinning the GKE cluster uses, but we recommend creating a separate service account. With a dedicated service account, one can grant permissions only necessary to the proxy. To create a service account:

$ gcloud iam service-accounts create proxy-service-account \
--display-name "Service account for Nomulus proxy"

Generate a .json key file for the newly created service account. The key file contains the secret necessary to construct credentials of the service account and needs to be stored safely (it should be deleted later).

$  gcloud iam service-accounts keys create proxy-key.json --iam-account \

A proxy-key.json file will be created inside the current working directory.

The client_id inside the key file needs to be added to the Nomulus configuration file so that Nomulus accepts the OAuth tokens generated for this service account. Add its value to java/google/registry/config/files/nomulus-config-<env>.yaml:

    - <client_id>

Redeploy Nomulus for the change to take effect.

Also bind the "Logs Writer" and role to the proxy service account so that it can write logs to Stackdriver Logging.

$ gcloud projects add-iam-policy-binding <project-id> \
--member serviceAccount:<service-accounte-email> \
--role roles/logging.logWriter

Obtain a domain and SSL certificate

A domain is needed (if you do not want to rely on IP addresses) for clients to communicate to the proxy. Domains can be purchased from a domain registrar (Google Domains for example). A Nomulus operator could also consider self-allocating a domain under an owned TLD insteadl.

An SSL certificate is needed as EPP over TCP requires SSL. You can apply for an SSL certificate for the domain name you intended to serve as EPP endpoint (epp.nic.tld for example) for free from Let's Encrypt. For now, you will need to manually renew your certificate before it expires.

Create keyring and encrypt the certificate/private key

The proxy needs access to both the private key and the certificate. Do not package them directly with the proxy. Instead, use Cloud KMS to encrypt them, ship the encrypted file with the proxy, and call Cloud KMS to decrypt them on the fly. (If you want to use another keyring solution, you will have to modify the proxy and implement yours)

Concatenate the private key file with the certificate. It does not matter which file is appended to which. However, if the certificate file is a chained .pem file, make sure that the certificates appear in order, i. e. the issuer of one certificate is the subject of the next certificate:

$ cat <private-key.key> <chained-certificates.pem> >> ssl-cert-key.pem

Create a keyring and a key in Cloud KMS, and use the key to encrypt the combined file:

# create keyring
$ gcloud kms keyrings create <keyring-name> --location global

# create key
$ gcloud kms keys create <key-name> --purpose encryption --location global \
--keyring <keyring-name>

# encryption using the key
$ gcloud kms encrypt --plaintext-file ssl-cert-key.pem \
--ciphertext-file ssl-cert-key.pem.enc \
--key <key-name> --keyring <keyring-name> --location global

A file named ssl-cert-key.pem.enc will be created. Upload it to a GCS bucket in the proxy project. To create a bucket and upload the file:

$ gsutil mb -p <proxy-project> gs://<bucket-name>
$ gustil cp ssl-cert-key.pem.enc gs://<bucket-name>

The proxy service account needs the "Cloud KMS CryptoKey Decrypter" role to decrypt the file using Cloud KMS:

$ gcloud projects add-iam-policy-binding <project-id> \
--member serviceAccount:<service-accounte-email> \
--role roles/cloudkms.cryptoKeyDecrypter

The service account also needs the "Storage Object Viewer" role to retrieve the encrypted file from GCS:

$ gsutil iam ch \
serviceAccount:<service-account-email>:roles/storage.objectViewer \

Proxy configuration

Proxy configuration files are at java/google/registry/proxy/config/. There is a default config that provides most values needed to run the proxy, and several environment-specific configs for proxy instances that communicate to different Nomulus environments. The values specified in the environment-specific file override those in the default file.

The values that need to be changed include the project name, the Nomulus endpoint, encrypted certificate/key combo filename (ssl-cert-key.pem in the above example), Cloud KMS keyring and key names, etc. Refer to the default file for detailed descriptions on each field.

Setup Stackdriver for the project

The proxy streams metrics to Stackdriver. Refer to Stackdriver Monitoring documentation on how to enable monitoring on the GCP project.

The proxy service account needs to have "Monitoring Metric Writer" role in order to stream metrics to Stackdriver:

$ gcloud projects add-iam-policy-binding <project-id> \
--member serviceAccount:<service-account-email> --role roles/monitoring.metricWriter

Create GKE clusters

We recommend creating several clusters in different zones for better geographical redundancy and better network performance. For example to have clusters in the Americas, EMEA and APAC. It is also a good idea to enable autorepair, autoupgrade, and autoscaling on the clusters.

The default Kubernetes version on GKE is usually old, consider specifying a newer version when creating the cluster, to save time upgrading the nodes immediately after.

$ gcloud container clusters create proxy-americas-cluster --enable-autorepair \
--enable-autoupgrade --enable-autoscaling --max-nodes=3 --min-nodes=1 \
--zone=us-east1-c --cluster-version=1.9.4-gke.1 --tags=proxy-cluster \

We give the GCE instances inside the cluster the same credential as the proxy service account, which makes it easier to limit permissions granted to service accounts. If we use the default GCE service account, we'd have to grant the default GCE service account permission to read from GCR in order to download images of the proxy to create pods, which gives any GCE instance with the default service account that permission.

Note the --tags flag: it will apply the tag to all GCE instances running in the cluster, making it easier to set up firewall rules later on. Use the same tag for all clusters.

Repeat this for all the zones you want to create clusters in.

Upload proxy docker image to GCR

The GKE deployment manifest is set up to pull the proxy docker image from Google Container Registry (GCR). Instead of using docker and gcloud to build and push images, respectively, we provide bazel rules for the same tasks. To push an image, first use docker-credential-gcr to obtain necessary credentials. It is used by the bazel container_push rules to push the image.

After credentials are configured, edit the proxy_push rule in java/google/registry/proxy/BUILD to add the GCP project name and the image name to save to. We recommend using the same project and image for proxies intended for different Nomulus environments, this way one can deploy the same proxy image first to sandbox for testing, and then to production.

Also note that as currently set up, all images pushed to GCR will be tagged bazel and the GKE deployment object loads the image tagged as bazel. This is fine for testing, but for production one should give images unique tags (also configured in the proxy_push rule).

To push to GCR, run:

$ bazel run java/google/registry/proxy:proxy_push

If the GCP project to host images (gcr project) is different from the project that the proxy runs in (proxy project), give the service account "Storage Object Viewer" role of the gcr project.

$ gcloud projects add-iam-policy-binding <image-project> \
--member serviceAccount:<service-account-email> \
--role roles/storage.objectViewer

Upload proxy service account key to GKE cluster

The kubernetes pods (containers) are configured to read the proxy service account key file from a secret resource stored in the cluster.

First set the cluster credential in gcloud so that kubectl knows which cluster to manage:

$ gcloud container clusters get-credentials proxy-americas-cluster \
--zone us-east1-c

To upload the key file as service-account-key.json as a secret named service-account:

$ kubectl create secret generic service-account \

More details on using service account on GKE can be found here.

Repeat the same step for all clusters you want to deploy to. Use gcloud to switch context, and then kubectl to upload the key.

Deploy proxy to GKE clusters

Use kubectl to create the deployment and autoscale objects:

$ kubectl create -f \

The kubernetes deployment object specifies the images to run, along with its parameters. The autoscale object changes the number of pods running based on CPU load. This is different from GKE cluster autoscaling, which changes the number of nodes (VMs) running based on pod resource requests. Ideally if there's no load, just one pod will be running in one cluster, resulting only one node running as well, saving resources.

Repeat the same step for all clusters you want to deploy to.

Expose the proxy service

The proxies running on GKE clusters need to be exposed to the outside. Do not use Kubernetes LoadBalancer. It will create a GCP Network Load Balancer, which has several problems:

  • This load balancer does not terminate TCP connections. It simply acts as an edge router that forwards IP packets to a "healthy" node in the cluster. As such, it does not support IPv6, because GCE instances themselves are currently IPv4 only.
  • IP packets that arrived on the node may be routed to another node for reasons of capacity and availability. In doing so it will SNAT the packet, therefore losing the source IP information that the proxy needs. The proxy uses WHOIS source IP address to cap QPS and passes EPP source IP to Nomulus for validation. Note that a TCP terminating load balancer also has this problem as the source IP becomes that of the load balancer, but it can be addressed in other ways (explained later). See here for more details on how Kubernetes route traffic and translate source IPs inside the cluster.
  • Acting as an edge router, this type of load balancer can only work with a given region as each GCP region forms its own subnet. Therefore multiple load balancers, and IP addresses are needed if the proxy were to run in multiple regional clusters.

Instead, we split the task of exposing the proxy to the Internet into two tasks, first to expose it within the cluster, then to expose the cluster to the outside through a TCP Proxy Load Balancer. This load balancer terminates TCP connections and allows for the use of a single anycast IP address (IPv4 and IPv6) to reach any clusters connected to its backend (it chooses a particular cluster based on geographical proximity). From this point forward we will refer to this type of load balancer simply as the load balancer.

Set up proxy NodePort service

Kubernetes pods and nodes are ephemeral. A pod may crash and be killed, and a new pod will be spun up by the master node to fill its role. Similarly a node may be shut down due to under-utilization (thanks to GKE autoscaling). In order to reliably route incoming traffic to the proxy, a NodePort service is used to expose the proxy on specificed port(s) on every running node in the cluster, even if the proxy does not run on a VM (in which case the traffic is routed to a VM that has the proxy running). With a [NodePort] service, the load balancer can alway route traffic to any healthy node, and kubernetes takes care of delivering that traffic to a servicing proxy pod.

To deploy the NodePort service:

$ kubectl create -f \

This service object will open up port 30000 (health check), 30001 (WHOIS) and 30002 (EPP) on the nodes, routing to the same ports inside a pod.

Repeat this for all clusters.

Map named ports in GCE instance groups

GKE uses GCE as its underlying infrastructure. A GKE cluster (or more precisely, a node pool) corresponds to a GKE instance group. In order to receive traffic from a load balancer backend, an instance group needs to designate the ports that are to receive traffic, by giving them names (i. e. making them "named ports").

As mentioned above, the Kubernetes NodePort service object sets up three ports to receive traffic (30000, 30001 and 30002). Port 30000 is used by the health check protocol (discussed later) and does not need to be explicitly named.

First obtain the instance group names for the clusters:

$ gcloud compute instance-groups list

They start with gke and have the cluster names in them, should be easy to spot.

Then set the named ports:

$ gcloud compute instance-groups set-named-ports <instance-group> \
--named-ports whois:30001,epp:30002 --zone <zone>

Repeat this for each instance group (cluster).

Set up firewall rules to allow traffic from the load balancer

By default inbound traffic from the load balancer are dropped by the GCE firewall. A new firewall rule needs to be added to explicitly allow TCP packets originating from the load balancer to the three ports opened in the NodePort service on the nodes.

$ gcloud compute firewall-rules create proxy-loadbalancer \
--source-ranges, \
--target-tags proxy-cluster \
--allow tcp:30000,tcp:30001,tcp:30002

The target tag controls what GCE VMs can receive traffic allowed in this rule. It is the same tag used during cluster creation. Since we use the same tag for all clusters, this rule applies to all VMs running the proxy. The load balancer source IP is taken from here

Create health check

The load balancer sends TCP requests to a designated port on each backend VM to probe if the VM is healthy to serve traffic. The proxy by default uses port 30000 (which is exposed as the same port on the node) for health check and returns a pre-configured response (HEALTH_CHECK_RESPONSE) when an expected request (HEALTH_CHECK_REQUEST) is received. To add health check:

$ gcloud compute health-checks create tcp proxy-health \
--description "Health check on port 30000 for Nomulus proxy" \
--port 30000 --request "HEALTH_CHECK_REQUEST" --response "HEALTH_CHECK_RESPONSE"

Create load balancer backend

The load balancer backend configures what instance groups the load balancer sends packets to. We have already setup NodePort service on each node in all the clusters to ensure that traffic to any of the exposed node ports will be routed to the corresponding port on a proxy pod. The backend service codifies which ports on the node's clusters should receive traffic from the load balancer.

Create one backend service for EPP and one for WHOIS:

# EPP backend
$ gcloud compute backend-services create proxy-epp-loadbalancer \
--global --protocol TCP --health-checks proxy-health --timeout 1h \
--port-name epp

# WHOIS backend
$ gcloud compute backend-services create proxy-whois-loadbalancer \
--global --protocol TCP --health-checks proxy-health --timeout 1h \
--port-name whois

These two backend services route packets to the epp named port and whois named port on any instance group attached to them, respectively.

Then add (attach) instance groups that the proxies run on to each backend service:

# EPP backend
$ gcloud compute backend-services add-backend proxy-epp-loadbalancer \
--global --instance-group <instance-group> --instance-group-zone <zone> \
--balancing-mode UTILIZATION --max-utilization 0.8

# WHOIS backend
$ gcloud compute backend-services add-backend proxy-whois-loadbalancer \
--global --instance-group <instance-group> --instance-group-zone <zone> \
--balancing-mode UTILIZATION --max-utilization 0.8

Repeat this for each instance group.

Reserve static IP addresses for the load balancer frontend

These are the public IP addresses that receive all outside traffic. We need one address for IPv4 and one for IPv6:

# IPv4
$ gcloud compute addresses create proxy-ipv4 \
--description "Global static anycast IPv4 address for Nomulus proxy" \
--ip-version IPV4 --global

# IPv6
$ gcloud compute addresses create proxy-ipv6 \
--description "Global static anycast IPv6 address for Nomulus proxy" \
--ip-version IPV6 --global

To check the IP addresses obtained:

$ gcloud compute addresses describe proxy-ipv4 --global
$ gcloud compute addresses describe proxy-ipv6 --global

Set these IP addresses as the A/AAAA records for both epp.<nic.tld> and whois.<nic.tld> where <nic.tld> is the domain that was obtained earlier. (If you use Cloud DNS as your DNS provider, this step can also be performed by gcloud)

Create load balancer frontend

The frontend receives traffic from the Internet and routes it to the backend service.

First create a TCP proxy (yes, it is confusing, this GCP resource is called "proxy" as well) which is a TCP termination point. Outside connections terminate on a TCP proxy, which establishes its own connection to the backend services defined above. As such, the source IP address from the outside is lost. But the TCP proxy can add the PROXY protocol header at the beginning of the connection to the backend. The proxy running on the backend can parse the header and obtain the original source IP address of a request.

Make one for each protocol (EPP and WHOIS).

$ gcloud compute target-tcp-proxies create proxy-epp-proxy \
--backend-service proxy-epp-loadbalancer --proxy-header PROXY_V1

$ gcloud compute target-tcp-proxies create proxy-whois-proxy \
--backend-service proxy-whois-loadbalancer --proxy-header PROXY_V1

Note the use of the --proxy-header flag, which turns on the PROXY protocol header.

Next, create the forwarding rule that route outside traffic to a given IP to the TCP proxy just created:

$ gcloud compute forwarding-rules create proxy-whois-ipv4 \
--global --target-tcp-proxy proxy-whois-proxy \
--address proxy-ipv4  --ports 43

The above command sets up a forwarding rule that routes traffic destined to the static IPv4 address reserved earlier, on port 43 (actual port for WHOIS), to the TCP proxy that connects to the whois backend service.

Repeat the above command another three times, set up IPv6 forwarding for WHOIS, and IPv4/IPv6 forwarding for EPP.

Additional steps

Check if it all works

At this point the proxy should be working and reachable from the Internet. Try if a whois request to it is successful:

whois -h whois.<nic.tld> something

One can also try to contact the EPP endpoint with an EPP client.

Check logs and metrics

The proxy saves logs to Stackdriver Logging, which is the same place that Nomulus saves it logs to. On GCP console, navigate to Logging - Logs - GKE Container - - default. Do not choose "All namespace_id" as it includes logs from the Kubernetes system itself and can be quite overwhelming.

Metrics are stored in Stackdriver Monitoring. To view the metrics, go to Stackdriver console (also accessible from GCE console under Monitoring), navigate to Resources - Metrics Explorer. Choose resource type "GKE Container" and search for metrics with name "/proxy/" in it. Currently available metrics include total connection counts, active connection count, request/response count, request/response size, round-trip latency and quota rejection count.

Cleanup sensitive files

Delete the service account key file and the SSL certificate private key, or store them in some secure location.