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 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 in environments where an external load balancer cannot be provisioned. See this how-to on how to configure keepalived-operator to support OpenShift ingresses
The keepalived operator will create one or more VIPs (an HA IP that floats between multiple nodes), based on the LoadBalancer services and/or services requesting ExternalIPs.
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 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 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:
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: <keepalivedgroup namespace>/<keepalivedgroup-name>
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.
Each KeepalivedGroup deploys a daemonset that requires the privileged scc, this permission must be given to the default service account in the namespace where the keepalived group is created by and administrator.
oc adm policy add-scc-to-user privileged -z default-n <keepalivedgroup namespace>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.autoAssignCIDRsdefines 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.policydefines the permissible IP address blocks when manually specifying an IP address. OpenShift does not apply policy rules to IP address blocks defined byspec.externalIP.autoAssignCIDRs
The following patch can be used to configure the Cluster Network Operator:
spec:
externalIP:
policy:
allowedCIDRs:
- ${ALLOWED_CIDR}
autoAssignCIDRs:
- "${AUTOASSIGNED_CIDR}"Here is an example of how to apply the patch:
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=mergeAdditionally, the fields can be edited manually via oc edit Network.config.openshift.io cluster
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.
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.
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:
podman run quay.io/openshift/origin-baremetal-runtimecfg:4.5 vr-ids <cluster_name>If you don't know your cluster name, run this command:
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 to blacklist those VRRP router IDs.
Keepalived has dozens of configurations. 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:
apiVersion: redhatcop.redhat.io/v1alpha1
kind: KeepalivedGroup
metadata:
name: keepalivedgroup-router
spec:
interface: ens3
nodeSelector:
node-role.kubernetes.io/loadbalancer: ""
verbatimConfig:
vrrp_iptables: my-keepalivedthis will map to the following global_defs:
global_defs {
router_id keepalivedgroup-router
vrrp_iptables my-keepalived
}
Service-level verbatim configurations can be passed as in the following example:
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
vrrp_instance openshift-ingress/router-default {
interface ens3
virtual_router_id 1
virtual_ipaddress {
192.168.131.129
}
track_src_ip
}
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.
Each keepalived pod exposes a Prometheus metrics port at 9650. Metrics are collected with keepalived_exporter, the available metrics are described in the project documentation.
When a keepalived group is created a 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:
podMonitorSelector:
matchLabels:
metrics: keepalivedIn 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:
oc label namespace <keepalived-group namespace> openshift.io/cluster-monitoring="true"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, but you can also deploy it using Helm.
| Arch | Support |
|---|---|
| amd64 | ✅ |
| arm64 | ✅ |
| ppc64le | ✅ |
| s390x | ❌ |
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.
- 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:
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 (
AutomaticorManual). - Once you've made your selection, you can select
Subscribeand the installation will begin. After a few moments you can go ahead and check your namespace and you should see the operator running.
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:
oc new-project keepalived-operator
oc apply -f config/operatorhub -n keepalived-operatorThis will create the appropriate OperatorGroup and Subscription and will trigger OLM to launch the operator in the specified namespace.
Here are the instructions to install the latest release with Helm.
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-operatorThis can later be updated with the following commands:
helm repo update
helm upgrade keepalived-operator keepalived-operator/keepalived-operatorPrometheus 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".
oc label namespace <namespace> openshift.io/cluster-monitoring="true"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
exitNote: this operator build process is tested with podman, 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.
export repo=raffaelespazzoli
docker login quay.io/$repo
oc new-project keepalived-operator
oc project keepalived-operator
tilt upDefine an image and tag. For example...
export imageRepository="quay.io/redhat-cop/keepalived-operator"
export imageTag="$(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...
make helmchart IMG=${imageRepository} VERSION=${imageTag}
helm upgrade -i keepalived-operator-local charts/keepalived-operator -n keepalived-operator-local --create-namespaceDelete...
helm delete keepalived-operator-local -n keepalived-operator-local
kubectl delete -f charts/keepalived-operator/crds/crds.yamlexport 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/$repo/keepalived-operator:latestmake manifests
make bundle IMG=quay.io/$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/$repo/keepalived-operator-bundle:latestmake helmchart-testAdd an external IP CIDR to your cluster to manage
export CIDR="192.168.130.128/28"
oc patch network cluster -p "$(envsubst < ./test/externalIP-patch.yaml | yq r -j -)" --type=mergecreate a project that uses a LoadBalancer Service
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=$(oc get svc django-psql-example -n test-keepalived-operator -o jsonpath='{.status.loadBalancer.ingress[0].ip}')create a keepalivedgroup
oc adm policy add-scc-to-user privileged -z default -n test-keepalived-operator
oc apply -f ./test/keepalivedgroup.yaml -n test-keepalived-operatorannotate the service to be used by keepalived
oc annotate svc django-psql-example -n test-keepalived-operator keepalived-operator.redhat-cop.io/keepalivedgroup=test-keepalived-operator/keepalivedgroup-testcurl the app using the service IP
curl http://$SERVICE_IP:8080test with a second keepalived group
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-operatorgit tag -a "<tagname>" -m "<commit message>"
git push upstream <tagname>If you need to remove a release:
git tag -d <tagname>
git push upstream --delete <tagname>If you need to "move" a release to the current main
git tag -f <tagname>
git push upstream -f <tagname>operator-sdk cleanup keepalived-operator -n keepalived-operator
oc delete operatorgroup operator-sdk-og
oc delete catalogsource keepalived-operator-catalog