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https://github.com/redhat-cop/keepalived-operator

An operator to manage VIPs backed by keepalived
https://github.com/redhat-cop/keepalived-operator

container-cop k8s-operator

Last synced: 7 months ago
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An operator to manage VIPs backed by keepalived

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README 

          
# Keepalived operator



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The objective of the keepalived operator is to allow for a way to create self-hosted load balancers in an automated way. From a user experience point of view the behavior is the same as of when creating [`LoadBalancer`](https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer) services with a cloud provider able to manage them.



The keepalived operator can be used in all environments that allows nodes to advertise additional IPs on their NICs (and at least for now, in networks that allow multicast), however it's mainly aimed at supporting LoadBalancer services and ExternalIPs on bare metal installations (or other installation environments where a cloud provider is not available).



One possible use of the keepalived operator is also to support [OpenShift Ingresses](https://docs.openshift.com/container-platform/4.5/networking/configuring_ingress_cluster_traffic/overview-traffic.html) in environments where an external load balancer cannot be provisioned. See this [how-to](./Ingress-how-to.md) on how to configure keepalived-operator to support OpenShift ingresses



## How it works



The keepalived operator will create one or more [VIPs](https://en.wikipedia.org/wiki/Virtual_IP_address) (an HA IP that floats between multiple nodes), based on the [`LoadBalancer`](https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer) services and/or services requesting [`ExternalIPs`](https://kubernetes.io/docs/concepts/services-networking/service/#external-ips).



For `LoadBalancer` services the IPs found at `.Status.LoadBalancer.Ingress[].IP` will become VIPs.



For services requesting a `ExternalIPs`, the IPs found at `.Spec.ExternalIPs[]` will become VIPs.



Note that a service can be of `LoadBalancer` type and also request `ExternalIPs`, it this case both sets of IPs will become VIPs.



Due to a [keepalived](https://www.keepalived.org/manpage.html) limitation a single keepalived cluster can manage up to 256 VIP configurations. Multiple keepalived clusters can coexists in the same network as long as they use different multicast ports [TODO verify this statement].



To address this limitation the `KeepalivedGroup` [CRD](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/) has been introduced. This CRD is supposed to be configured by an administrator and allows you to specify a node selector to pick on which nodes the keepalived pods should be deployed. Here is an example:



```yaml

apiVersion: redhatcop.redhat.io/v1alpha1

kind: KeepalivedGroup

metadata:

  name: keepalivedgroup-router

spec:

  image: registry.redhat.io/openshift4/ose-keepalived-ipfailover

  interface: ens3

  nodeSelector:

    node-role.kubernetes.io/loadbalancer: ""

  blacklistRouterIDs:

  - 1

  - 2  

```



This KeepalivedGroup will be deployed on all the nodes with role `loadbalancer`. Keepalived requires knowledge of the network device on which the VIPs will be exposed. If the interface name is the same on all nodes, it can be specified in the `interface` field. Alternatively, the `interfaceFromIP` field can be set to an IPv4 address to enable interface autodiscovery. In this scenario, the `interface` field will be ignored and each node in the KeepalivedGroup will expose the VIPs on the interface that would be used to reach the provided IP.



Services must be annotated to opt-in to being observed by the keepalived operator and to specify which KeepalivedGroup they refer to. The annotation looks like this:



`keepalived-operator.redhat-cop.io/keepalivedgroup: /`



The image used for the keepalived containers can be specified with `.Spec.Image` it will default to `registry.redhat.io/openshift4/ose-keepalived-ipfailover` if undefined.



## Requirements



### Security Context Constraints



Each KeepalivedGroup deploys a [daemonset](https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/) that requires the [privileged scc](https://docs.openshift.com/container-platform/4.5/authentication/managing-security-context-constraints.html), this permission must be given to the `default` service account in the namespace where the keepalived group is created by and administrator.



```shell

oc adm policy add-scc-to-user privileged -z default-n 

```



### Cluster Network Operator



In Openshift, use of an external IP address is governed by the following fields in the `Network.config.openshift.io` CR named `cluster`



* `spec.externalIP.autoAssignCIDRs` defines an IP address block used by the load balancer when choosing an external IP address for the service. OpenShift supports only a single IP address block for automatic assignment.



* `spec.externalIP.policy` defines the permissible IP address blocks when manually specifying an IP address. OpenShift does not apply policy rules to IP address blocks defined by `spec.externalIP.autoAssignCIDRs`



The following patch can be used to configure the Cluster Network Operator:



```yaml

spec:

  externalIP:

    policy:

      allowedCIDRs:

      - ${ALLOWED_CIDR}

    autoAssignCIDRs:

      - "${AUTOASSIGNED_CIDR}"

```



Here is an example of how to apply the patch:



```shell

export ALLOWED_CIDR="192.168.131.128/26"

export AUTOASSIGNED_CIDR="192.168.131.192/26"

oc patch network cluster -p "$(envsubst < ./network-patch.yaml | yq r -j -)" --type=merge

```



Additionally, the fields can be edited manually via `oc edit Network.config.openshift.io cluster`



## Blacklisting router IDs



If the Keepalived pods are deployed on nodes which are in the same network (same broadcast domain to be precise) with other keepalived the process, it's necessary to ensure that there is no collision between the used routers it.

For this purpose it is possible to provide a `blacklistRouterIDs` field with a list of black-listed IDs that will not be used.



## Spreading VIPs across nodes to maximize load balancing



If a service contains multiple externalIPs or LoadBalancer IPs, it is possible to instruct keepalived-operator to maximize the spread of such VIPs across the nodes in the KeepalivedGroup by specifying the `keepalived-operator.redhat-cop.io/spreadvips: "true"` annotation on the service. This option ensures that different VIPs for the same service are always owned by different nodes (or, if the number of nodes in the group is less than the number of VIPs, that the VIPs are assigned maximizing the spread), to avoid creating a traffic bottleneck. However, in order to achieve this, keepalived-operator will create a separate VRRP instance per VIP of that service, which could exhaust the 256 available instances faster.



## OpenShift RHV, vSphere, OSP and bare metal IPI instructions



When IPI is used for RHV, vSphere, OSP or bare metal platforms, three keepalived VIPs are deployed. To make sure that keepalived-operator can work in these environment we need to discover and blacklist the corresponding VRRP router IDs.



To discover the VRRP router IDs being used, run the following command, you can run this command from you laptop:



```shell

podman run quay.io/openshift/origin-baremetal-runtimecfg:4.5 vr-ids 

```



If you don't know your cluster name, run this command:



```shell

podman run quay.io/openshift/origin-baremetal-runtimecfg:4.5 vr-ids $(oc get cm cluster-config-v1 -n kube-system -o jsonpath='{.data.install-config}'| yq -r .metadata.name)

```



Then use these [instructions](#Blacklisting-router-IDs) to blacklist those VRRP router IDs.



## Verbatim Configurations



Keepalived has dozens of [configurations](https://www.keepalived.org/manpage.html). At the early stage of this project it's difficult to tell which one should be modeled in the API. Yet, users of this project may still need to use them. To account for that there is a way to pass verbatim options both at the keepalived group level (which maps to the keepalived config `global_defs` section) and at the service level (which maps to the keepalived config `vrrp_instance` section).



KeepalivedGroup-level verbatim configurations can be passed as in the following example:



```yaml

apiVersion: redhatcop.redhat.io/v1alpha1

kind: KeepalivedGroup

metadata:

  name: keepalivedgroup-router

spec:

  interface: ens3

  nodeSelector:

    node-role.kubernetes.io/loadbalancer: ""

  verbatimConfig:  

    vrrp_iptables: my-keepalived

```



this will map to the following `global_defs`:



```text

    global_defs {

        router_id keepalivedgroup-router

        vrrp_iptables my-keepalived

    }

```



Service-level verbatim configurations can be passed as in the following example:



```yaml

apiVersion: v1

kind: Service

metadata:

  annotations:

    keepalived-operator.redhat-cop.io/keepalivedgroup: keepalived-operator/keepalivedgroup-router

    keepalived-operator.redhat-cop.io/verbatimconfig: '{ "track_src_ip": "" }'

```



this will map to the following `vrrp_instance` section



```text

    vrrp_instance openshift-ingress/router-default {

        interface ens3

        virtual_router_id 1  

        virtual_ipaddress {

          192.168.131.129

        }

        track_src_ip

    }

```



## Advanced Users Only: Override Keepalived Configuration Template



**NOTE**: This config customization feature can only be used via Helm.



Each of the Keepalived daemon pods gets received it's configuration from a ConfigMap that gets generated by the Keepalived Operator from a configuration file template.

If you need to customize the configuration for your Keepalived daemon pods, you'll want to use the following steps.



Create a ConfigMap with the full contents of this configuration template file:

https://github.com/redhat-cop/keepalived-operator/blob/master/config/templates/keepalived-template.yaml



```

apiVersion: v1

kind: ConfigMap

metadata:

name: keepalived-template

namespace: {{ .KeepalivedGroup.ObjectMeta.Namespace }}

labels:

  keepalivedGroup: {{ .KeepalivedGroup.ObjectMeta.Name }}    

data: 

keepalived.conf: |

    ...

    # expected merge structure

    # .KeepAlivedGroup

    # .Services

    - apiVersion: apps/v1

      kind: DaemonSet

      metadata:

        name: {{ .KeepalivedGroup.ObjectMeta.Name }}

        namespace: {{ .KeepalivedGroup.ObjectMeta.Namespace }}

      spec:

    ...

```

  

Then in the Helm Chart set `keepalivedTemplateFromConfigMap: keepalived-template`



This will override the `/templates/keepalived-template.yaml` config file in the keepalived-operator pod which will allow you to update the configs without having to rebuild/push the operator docker image.



## Metrics collection



Each keepalived pod exposes a [Prometheus](https://prometheus.io/) metrics port at `9650`. Metrics are collected with [keepalived_exporter](github.com/gen2brain/keepalived_exporter), the available metrics are described in the project documentation.



When a keepalived group is created a [`PodMonitor`](https://github.com/coreos/prometheus-operator/blob/master/Documentation/api.md#podmonitor) rule to collect those metrics. All PodMonitor resources created that way have the label: `metrics: keepalived`. It is up to you to make sure your Prometheus instance watches for those `PodMonitor` rules. Here is an example of a fragment of a `Prometheus` CR configured to collect the keepalived pod metrics:



```yaml

  podMonitorSelector:

    matchLabels:

      metrics: keepalived

```



In order to enable the collection of these metrics by the platform prometheus you have to appropriately label the namespace in which the `KeepalivedGroup` CR was created:



```shell

oc label namespace  openshift.io/cluster-monitoring="true"

```



## Deploying the Operator



This is a cluster-level operator that you can deploy in any namespace, `keepalived-operator` is recommended.



It is recommended to deploy this operator via [`OperatorHub`](https://operatorhub.io/), but you can also deploy it using [`Helm`](https://helm.sh/).



### Multiarch Support



| Arch  | Support  |

|:-:|:-:|

| amd64  | ✅ |

| arm64  | ✅  |

| ppc64le  | ✅  |

| s390x  | ❌  |



### Deploying from OperatorHub



> **Note**: This operator supports being installed disconnected environments



If you want to utilize the Operator Lifecycle Manager (OLM) to install this operator, you can do so in two ways: from the UI or the CLI.



#### Deploying from OperatorHub UI



* If you would like to launch this operator from the UI, you'll need to navigate to the OperatorHub tab in the console.Before starting, make sure you've created the namespace that you want to install this operator to with the following:



```shell

oc new-project keepalived-operator

```



* Once there, you can search for this operator by name: `keepalived`. This will then return an item for our operator and you can select it to get started. Once you've arrived here, you'll be presented with an option to install, which will begin the process.

* After clicking the install button, you can then select the namespace that you would like to install this to as well as the installation strategy you would like to proceed with (`Automatic` or `Manual`).

* Once you've made your selection, you can select `Subscribe` and the installation will begin. After a few moments you can go ahead and check your namespace and you should see the operator running.



![Keepalived Operator](./media/keepalived-operator.png)



#### Deploying from OperatorHub using CLI



If you'd like to launch this operator from the command line, you can use the manifests contained in this repository by running the following:



```shell

oc new-project keepalived-operator

oc apply -f config/operatorhub -n keepalived-operator

```



This will create the appropriate OperatorGroup and Subscription and will trigger OLM to launch the operator in the specified namespace.



### Deploying with Helm



Here are the instructions to install the latest release with Helm.



```shell

oc new-project keepalived-operator

helm repo add keepalived-operator https://redhat-cop.github.io/keepalived-operator

helm repo update

helm install keepalived-operator keepalived-operator/keepalived-operator

```



This can later be updated with the following commands:



```shell

helm repo update

helm upgrade keepalived-operator keepalived-operator/keepalived-operator

```



## Metrics



Prometheus compatible metrics are exposed by the Operator and can be integrated into OpenShift's default cluster monitoring. To enable OpenShift cluster monitoring, label the namespace the operator is deployed in with the label `openshift.io/cluster-monitoring="true"`.



```shell

oc label namespace  openshift.io/cluster-monitoring="true"

```



### Testing metrics



```sh

export operatorNamespace=keepalived-operator-local # or keepalived-operator

oc label namespace ${operatorNamespace} openshift.io/cluster-monitoring="true"

oc rsh -n openshift-monitoring -c prometheus prometheus-k8s-0 /bin/bash

export operatorNamespace=keepalived-operator-local # or keepalived-operator

curl -v -s -k -H "Authorization: Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" https://keepalived-operator-controller-manager-metrics.${operatorNamespace}.svc.cluster.local:8443/metrics

exit

```



## Development



### Running the operator locally



> Note: this operator build process is tested with [podman](https://podman.io/), but some of the build files (Makefile specifically) use docker because they are generated automatically by operator-sdk. It is recommended [remap the docker command to the podman command](https://developers.redhat.com/blog/2020/11/19/transitioning-from-docker-to-podman#transition_to_the_podman_cli).



```shell

export repo=raffaelespazzoli

docker login quay.io/$repo

oc new-project keepalived-operator

oc project keepalived-operator

tilt up

```



### Test helm chart locally



Define an image and tag. For example...



```shell

export imageRepository="quay.io/redhat-cop/keepalived-operator"

export imageTag="$(git -c 'versionsort.suffix=-' ls-remote --exit-code --refs --sort='version:refname' --tags https://github.com/redhat-cop/keepalived-operator.git '*.*.*' | tail --lines=1 | cut --delimiter='/' --fields=3)"

```



Deploy chart...



```shell

make helmchart IMG=${imageRepository} VERSION=${imageTag}

helm upgrade -i keepalived-operator-local charts/keepalived-operator -n keepalived-operator-local --create-namespace

```



Delete...



```shell

helm delete keepalived-operator-local -n keepalived-operator-local

kubectl delete -f charts/keepalived-operator/crds/crds.yaml

```



### Building/Pushing the operator image



```shell

export repo=raffaelespazzoli #replace with yours

docker login quay.io/$repo/keepalived-operator

make docker-build IMG=quay.io/$repo/keepalived-operator:latest

make docker-push IMG=quay.io/$repo/keepalived-operator:latest

```



### Deploy to OLM via bundle



```shell

make manifests

make bundle IMG=quay.io/$repo/keepalived-operator:latest

operator-sdk bundle validate ./bundle --select-optional name=operatorhub

make bundle-build BUNDLE_IMG=quay.io/$repo/keepalived-operator-bundle:latest

docker login quay.io/$repo/keepalived-operator-bundle

docker push quay.io/$repo/keepalived-operator-bundle:latest

operator-sdk bundle validate quay.io/$repo/keepalived-operator-bundle:latest --select-optional name=operatorhub

oc new-project keepalived-operator

oc label namespace keepalived-operator openshift.io/cluster-monitoring="true" --overwrite

operator-sdk cleanup keepalived-operator -n keepalived-operator

operator-sdk run bundle --install-mode AllNamespaces -n keepalived-operator quay.io/$repo/keepalived-operator-bundle:latest

```



## Integration Test



```sh

make helmchart-test

```



### Testing



Add an external IP CIDR to your cluster to manage



```shell

export CIDR="192.168.130.128/28"

oc patch network cluster -p "$(envsubst < ./test/externalIP-patch.yaml | yq r -j -)" --type=merge

```



create a project that uses a LoadBalancer Service



```shell

oc new-project test-keepalived-operator

oc new-app django-psql-example -n test-keepalived-operator

oc delete route django-psql-example -n test-keepalived-operator

oc patch service django-psql-example -n test-keepalived-operator -p '{"spec":{"type":"LoadBalancer"}}' --type=strategic

export SERVICE_IP=$(oc get svc django-psql-example -n test-keepalived-operator -o jsonpath='{.status.loadBalancer.ingress[0].ip}')

```



create a keepalivedgroup



```shell

oc adm policy add-scc-to-user privileged -z default -n test-keepalived-operator

oc apply -f ./test/keepalivedgroup.yaml -n test-keepalived-operator

```



annotate the service to be used by keepalived



```shell

oc annotate svc django-psql-example -n test-keepalived-operator keepalived-operator.redhat-cop.io/keepalivedgroup=test-keepalived-operator/keepalivedgroup-test

```



curl the app using the service IP



```shell

curl http://$SERVICE_IP:8080

```



test with a second keepalived group



```shell

oc apply -f ./test/test-servicemultiple.yaml -n test-keepalived-operator

oc apply -f ./test/keepalivedgroup2.yaml -n test-keepalived-operator

oc apply -f ./test/test-service-g2.yaml -n test-keepalived-operator

```



### Releasing



```shell

git tag -a "" -m ""

git push upstream 

```



If you need to remove a release:



```shell

git tag -d 

git push upstream --delete 

```



If you need to "move" a release to the current main



```shell

git tag -f 

git push upstream -f 

```



### Cleaning up



```shell

operator-sdk cleanup keepalived-operator -n keepalived-operator

oc delete operatorgroup operator-sdk-og

oc delete catalogsource keepalived-operator-catalog

```