--- title: Kubernetes reverse proxy summary: null url: >- https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-reverse-proxy --- In this example, the Next-Gen WAF agent runs in a sidecar container and proxies all incoming requests for inspection before sending them upstream to the application container. ## Integrating the Next-Gen WAF agent The Next-Gen WAF agent can be installed as a sidecar into each pod or as a service for some specialized needs. The recommended way of installing the Next-Gen WAF agent in Kubernetes is by integrating the `sigsci-agent` into a pod as a [sidecar](https://matthewpalmer.net/kubernetes-app-developer/articles/multi-container-pod-design-patterns.html). This means adding the `sigsci-agent` as an additional container to the Kubernetes pod. As a sidecar, the agent will scale with the app/service in the pod instead of having to do this separately. However, in some situations, it may make more sense to install the `sigsci-agent` container as a service and [scale it separately from the application](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-agent-scaling). The `sigsci-agent` container can be configured in various ways depending on the installation type and module being used. You can use the [`preStop` container hook](https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/#container-hooks) to slow the pod's shutdown and ensure drain timeouts are met. ```yaml preStop: exec: command: - sleep - "30" ``` By default, the agent prioritizes quick start up and performance readiness for preliminary inspection. However, quick startup isn't always desirable if you only want the agent to inspect traffic after loading your rules and configuration data. If you want to delay agent startup, consider configuring a [startup probe](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-startup-probe). ## Getting and updating the agent container image An official `signalsciences/sigsci-agent` container image is available on [Docker Hub](https://hub.docker.com/r/signalsciences/sigsci-agent). Alternatively, if you want to build your own image or need to customize the image, then follow the [sigsci-agent build instructions](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-agent/). These instructions reference the `latest` version of the agent with `imagePullPolicy: Always`, which will pull the latest agent version even if one already exist locally. This is so the documentation does not fall out of date and anyone using this will not have an agent that stays stagnant. However, this may not be what if you need to keep installations consistent or on a specific version of the agent. In these cases, you should specify an [agent version](https://www.fastly.com/documentation/reference/changes/ngwaf-agent/). Images on Docker Hub are tagged with their versions and [a list of versions is available on Docker Hub](https://hub.docker.com/r/signalsciences/sigsci-agent/tags). Whether you choose to use the `latest` image or a specific version, there are a few items to consider to keep the agent up-to-date. ### Using the `latest` container image If you do choose to use the `latest` image, then you will want to consider how you will keep the agent up to date. - If you have used the `imagePullPolicy: Always` option, then the latest image will be pulled on each startup and your agent will continue to get updates. - Alternatively, you may instead choose to manually update the local cache by periodically forcing a pull instead of always pulling on startup: ```term $ docker pull signalsciences/sigsci-agent:latest ``` Then, use `latest` with `imagePullPolicy: Never` set in the configuration so that pulls are never done on startup (only manually as above): ```yaml - name: sigsci-agent image: signalsciences/sigsci-agent:latest imagePullPolicy: Never ... ``` ### Using a versioned container image To use a specific version of the agent, replace `latest` with the agent version (represented here by `x.xx.x`). You may also want to change `imagePullPolicy: IfNotPresent` in this case as the image should not change. ```yaml - name: sigsci-agent image: signalsciences/sigsci-agent:x.xx.x imagePullPolicy: IfNotPresent ... ``` This will pull the specified agent version and cache it locally. If you use this method, then it is recommended that you parameterize the agent image, using Helm or similar, so that it is easier to update the agent images later on. ### Using a custom tag for the container image It is also possible to apply a custom tag to a local agent image. To do this, pull the agent image (by version or use `latest`), apply a custom tag, then use that custom tag in the configuration. You will need to specify `imagePullPolicy: Never` so local images are only updated manually. After doing so, you will need to periodically update the local image to keep the agent up-to-date. For example: ```term $ docker pull signalsciences/sigsci-agent:latest $ docker tag signalsciences/sigsci-agent:latest signalsciences/sigsci-agent:testing ``` Then use this image tag in the configuration: ```yaml - name: sigsci-agent image: signalsciences/sigsci-agent:testing imagePullPolicy: Never ... ``` ## Configuring the agent container Agent configuration is normally done via the environment. Most configuration options are available as environment variables. Environment variables names have the configuration option name all capitalized, prefixed with `SIGSCI_` and any dashes (-) changed to underscores (\_). For example, the [max-procs](https://www.fastly.com/documentation/reference/ngwaf/agent-config#agentcfg_max-procs) option would become the `SIGSCI_MAX_PROCS` environment variable. For more details on what options are available, see the [Agent Configuration documentation](https://www.fastly.com/documentation/reference/ngwaf/agent-config). The `sigsci-agent` container has a few required options that need to be configured: - Agent credentials (**Agent Access Key** and **Agent Secret Key**). - A volume to write temporary files. ### Agent credentials The [`sigsci-agent` credentials](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/agent-management/accessing-agent-keys) are configured with two environment variables. These variables must be set or the agent will not start. - **SIGSCI_ACCESSKEYID**: The **Agent Access Key** identifies which site (also known as workspace) the agent is configured for. - **SIGSCI_SECRETACCESSKEY**: The **Agent Secret Key** is the shared secret key to authenticate and authorize the agent. Because of the sensitive nature of these values, we recommend you use the built in `secrets` functionality of Kubernetes. With this configuration, the agent will pull the values from the secrets data instead of reading hardcoded values into the deployment configuration. This also makes any desired agent credential rotation easier to manage by having to change them in only one place. Use the `valueFrom` option instead of the `value` option to use the `secrets` functionality. For example: ```yaml env: - name: SIGSCI_ACCESSKEYID valueFrom: secretKeyRef: # Update my-site-name-here to the correct site (workspace) name or similar identifier name: sigsci.my-site-name-here key: accesskeyid - name: SIGSCI_SECRETACCESSKEY valueFrom: secretKeyRef: # Update my-site-name-here to the correct site (workspace) name or similar identifier name: sigsci.my-site-name-here key: secretaccesskey ``` The `secrets` functionality keeps secrets in various stores in Kubernetes. This guide uses the generic secret store in its examples, however any equivalent store can be used. Agent secrets can be added to the generic secret store using YAML similar to the following example: ```yaml apiVersion: v1 kind: Secret metadata: name: sigsci.my-site-name-here stringData: accesskeyid: 12345678-abcd-1234-abcd-1234567890ab secretaccesskey: abcdefg_hijklmn_opqrstuvwxy_z0123456789ABCD ``` This can also be created from the command line with `kubectl` such as with the following example: ```term $ kubectl create secret generic sigsci.my-site-name-here \ --from-literal=accesskeyid=12345678-abcd-1234-abcd-1234567890ab \ --from-literal=secretaccesskey=abcdefg_hijklmn_opqrstuvwxy_z0123456789ABCD ``` Additional information about Kubernetes `secrets` functionality can be found in the [Kubernetes documentation](https://kubernetes.io/docs/concepts/configuration/secret/). ### Agent temporary volume For added security, we recommended the `sigsci-agent` container be executed with the root filesystem mounted as read only. However, the agent still needs to write some temporary files such as the socket file for RPC communication and some periodically updated files such as geolocation data. To accomplish this with a read only root filesystem, there needs to be a writeable volume mounted. This writeable volume can also be shared to expose the RPC socket file to other containers in the same pod. The recommended way of creating a writeable volume is to use the builtin `emptyDir` volume type. This is typically configured in the `volumes` section of a deployment, as shown in the following example: ```yaml volumes: - name: sigsci-tmp emptyDir: {} ``` Containers will then mount this volume at `/sigsci/tmp`: ```yaml volumeMounts: - name: sigsci-tmp mountPath: /sigsci/tmp ``` The default in the official agent container image is to have the temporary volume mounted at `/sigsci/tmp`. If this needs to be moved for the agent container, then the following agent configuration options should also be changed from their defaults to match the new mount location: - `rpc-address` defaults to `/sigsci/tmp/sigsci.sock` - `shared-cache-dir` defaults to `/sigsci/tmp/cache` ## Next-Gen WAF agent as a reverse proxy in front of a web application without the Next-Gen WAF module If your web application does not support a Next-Gen WAF module (or you prefer not to install a module), then you can configure the `sigsci-agent` container to run as a reverse proxy in front of the web application in the same pod. To configure the Next-Gen WAF agent to run in reverse proxy mode in a sidecar container, you must: - Add the `sigsci-agent` container to the pod, configured in reverse proxy mode to: - listen for incoming requests (on a new port or by reconfiguring your application or Kubernetes service accordingly) - proxy requests to your web application container - Add an `emptyDir{}` volume as a place for the `sigsci-agent` to write temporary data. The following configuration exposes an [example application (`helloworld`)](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/example-helloworld) on port `8000`, adding the `sigsci-agent` as a reverse proxy listener on a new port `8001` with an upstream of the example web application port `8000`. ### Add the Next-Gen WAF agent as a reverse proxy ```yaml ... containers: # Example helloworld app running on port 8000 without sigsci configured - name: helloworld image: signalsciences/example-helloworld:latest imagePullPolicy: IfNotPresent args: - localhost:8000 ports: - containerPort: 8000 # Next-Gen WAF agent running in reverse proxy mode (SIGSCI_REVPROXY_LISTENER configured) - name: sigsci-agent image: signalsciences/sigsci-agent:latest imagePullPolicy: Always env: - name: SIGSCI_ACCESSKEYID valueFrom: secretKeyRef: name: sigsci.my-site-name-here key: accesskeyid - name: SIGSCI_SECRETACCESSKEY valueFrom: secretKeyRef: name: sigsci.my-site-name-here key: secretaccesskey # Configure the revproxy listener to listen on a new port 8001 # forwarding to the app on the original port 8000 as the upstream - name: SIGSCI_REVPROXY_LISTENER value: "http:{listener='http://0.0.0.0:8001',upstreams='http://0.0.0.0:8000',access-log='/dev/stdout'}" ports: - containerPort: 8001 securityContext: # The sigsci-agent container should run with its root filesystem read only readOnlyRootFilesystem: true volumeMounts: # Default volume mount location for sigsci-agent writeable data # NOTE: Also change `SIGSCI_SHARED_CACHE_DIR` (default `/sigsci/tmp/cache`) # if mountPath is changed, but best not to change. - name: sigsci-tmp mountPath: /sigsci/tmp ``` > **NOTE:** The above modification assumes that `sigsci` secrets were added to the system. ### Adding the Next-Gen WAF agent temp volume definition to the deployment You must define the agent temp volume for use by the other containers in the pod. This example uses the builtin `emptyDir: {}` volume type. ```yaml ... volumes: # Define a volume where sigsci-agent will write temp data and share the socket file, # which is required with the root filesystem is mounted read only - name: sigsci-tmp emptyDir: {} ``` ## Changing the service definition and adding the Next-Gen WAF agent as a reverse proxy In the example above, the `sigsci-agent` reverse proxy listens on a new port, leaving the original application listener in place. You may wish for requests to be routed to the `sigsci-agent` at the original application port to make the agent addition as seamless as possible. One way to do this is to modify the Kubernetes _service definition_ to route traffic to the `sigsci-agent` reverse proxy listener port instead of directly to the web application. ### Change the service definition to point to the Next-Gen WAF agent port Change the service `targetPort` from pointing directly to the application, to instead point to the `sigsci-agent` reverse proxy listener port. The `sigsci-agent` will then proxy to the application port: ```yaml apiVersion: v1 kind: Service metadata: name: helloworld labels: app: helloworld spec: ports: - name: http port: 8000 # Target is now sigsci-agent on port 8001 targetPort: 8001 selector: app: helloworld type: LoadBalancer ``` ## Related content - [Kubernetes installation overview](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-intro) - [Kubernetes agent scaling](https://www.fastly.com/documentation/guides/next-gen-waf/setup-and-configuration/kubernetes/kubernetes-agent-scaling)