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A Helm chart for Running VMCluster on Multiple Availability Zones

Prerequisites #

• Install the follow packages: git, kubectl, helm, helm-docs. See this tutorial.

• PV support on underlying infrastructure.

• Multiple availability zones.

Chart Details #

This chart sets up multiple VictoriaMetrics cluster instances on multiple availability zones, provides both global write and read entrypoints.

The default setup is as shown below:

For write:

1. extra-vmagent(optional): scrapes external targets and all the components installed by this chart, sends data to global write entrypoint.
2. vmauth-global-write: global write entrypoint, proxies requests to one of the zone vmagent with least_loaded policy.
3. vmagent(per-zone): remote writes data to availability zones that enabled .Values.availabilityZones[*].write.allow, and buffer data on disk when zone is unavailable to ingest.
4. vmauth-write-balancer(per-zone): proxies requests to vminsert instances inside it’s zone with least_loaded policy.
5. vmcluster(per-zone): processes write requests and stores data.

For read:

1. vmcluster(per-zone): processes query requests and returns results.
2. vmauth-read-balancer(per-zone): proxies requests to vmselect instances inside it’s zone with least_loaded policy.
3. vmauth-read-proxy(per-zone): uses all the vmauth-read-balancer as servers if zone has .Values.availabilityZones[*].read.allow enabled, always prefer “local” vmauth-read-balancer to reduce cross-zone traffic with first_available policy.
4. vmauth-global-read: global query entrypoint, proxies requests to one of the zone vmauth-read-proxy with first_available policy.
5. grafana(optional): uses vmauth-global-read as default datasource.

Note: As the topology shown above, this chart doesn’t include components like vmalert, alertmanager, etc by default. You can install them using dependency victoria-metrics-k8s-stack or having separate release.

Why use victoria-metrics-distributed chart? #

One of the best practice of running production kubernetes cluster is running with multiple availability zones. And apart from kubernetes control plane components, we also want to spread our application pods on multiple zones, to continue serving even if zone outage happens.

VictoriaMetrics supports data replication natively which can guarantees data availability when part of the vmstorage instances failed. But it doesn’t works well if vmstorage instances are spread on multiple availability zones, since data replication could be stored on single availability zone, which will be lost when zone outage happens. To avoid this, vmcluster must be installed on multiple availability zones, each containing a 100% copy of data. As long as one zone is available, both global write and read entrypoints should work without interruption.

How to write data? #

The chart provides vmauth-global-write as global write entrypoint, it supports push-based data ingestion protocols as VictoriaMetrics does. Optionally, you can push data to any of the per-zone vmagents, and they will replicate the received data across zones.

How to query data? #

The chart provides vmauth-global-read as global read entrypoint, it picks the first available zone (see first_available policy) as it’s preferred datasource and switches automatically to next zone if first one is unavailable, check vmauth first_available for more details. If you have services like vmalert or Grafana deployed in each zone, then configure them to use local vmauth-read-proxy. Per-zone vmauth-read-proxy always prefers “local” vmcluster for querying and reduces cross-zone traffic.

You can also pick other proxies like kubernetes service which supports Topology Aware Routing as global read entrypoint.

What happens if zone outage happen? #

If availability zone zone-eu-1 is experiencing an outage, vmauth-global-write and vmauth-global-read will work without interruption:

1. vmauth-global-write stops proxying write requests to zone-eu-1 automatically;
2. vmauth-global-read and vmauth-read-proxy stops proxying read requests to zone-eu-1 automatically;
3. vmagent on zone-us-1 fails to send data to zone-eu-1.vmauth-write-balancer, starts to buffer data on disk(unless -remoteWrite.disableOnDiskQueue is specified, which is not recommended for this topology); To keep data completeness for all the availability zones, make sure you have enough disk space on vmagent for buffer, see this doc for size recommendation.

And to avoid getting incomplete responses from zone-eu-1 which gets recovered from outage, check vmagent on zone-us-1 to see if persistent queue has been drained. If not, remove zone-eu-1 from serving query by setting .Values.availabilityZones.{zone-eu-1}.read.allow=false and change it back after confirm all data are restored.

How to use multitenancy? #

By default, all the data that written to vmauth-global-write belong to tenant 0. To write data to different tenants, set .Values.enableMultitenancy=true and create new tenant users for vmauth-global-write. For example, writing data to tenant 1088 with following steps:

1. create tenant VMUser for vmauth vmauth-global-write to use:

apiVersion: operator.victoriametrics.com/v1beta1
kind: VMUser
metadata:
  name: tenant-1088-rw
  labels:
    tenant-test: "true"
spec:
  targetRefs:
  - static:
      ## list all the zone vmagent here
      url: "http://vmagent-vmagent-zone-eu-1:8429"
      url: "http://vmagent-vmagent-zone-us-1:8429"
    paths:
    - "/api/v1/write"
    - "/prometheus/api/v1/write"
    - "/write"
    - "/api/v1/import"
    - "/api/v1/import/.+"
    target_path_suffix: /insert/1088/
  username: tenant-1088
  password: secret

Add extra VMUser selector in vmauth vmauth-global-write

spec:
  userSelector:
    matchLabels:
      tenant-test: "true"

2. send data to vmauth-global-write using above token. Example command using vmagent:

/path/to/vmagent -remoteWrite.url=http://vmauth-vmauth-global-write-$ReleaseName-vm-distributed:8427/prometheus/api/v1/write -remoteWrite.basicAuth.username=tenant-1088 -remoteWrite.basicAuth.password=secret

How to install #

Access a Kubernetes cluster.

Setup chart repository (can be omitted for OCI repositories) #

Add a chart helm repository with follow commands:

helm repo add vm https://victoriametrics.github.io/helm-charts/

helm repo update

List versions of vm/victoria-metrics-distributed chart available to installation:

helm search repo vm/victoria-metrics-distributed -l

Install victoria-metrics-distributed chart #

Export default values of victoria-metrics-distributed chart to file values.yaml:

• For HTTPS repository

  helm show values vm/victoria-metrics-distributed > values.yaml
  

• For OCI repository

  helm show values oci://ghcr.io/victoriametrics/helm-charts/victoria-metrics-distributed > values.yaml
  

Change the values according to the need of the environment in values.yaml file.

Test the installation with command:

• For HTTPS repository

  helm install vmd vm/victoria-metrics-distributed -f values.yaml -n NAMESPACE --debug --dry-run
  

• For OCI repository

  helm install vmd oci://ghcr.io/victoriametrics/helm-charts/victoria-metrics-distributed -f values.yaml -n NAMESPACE --debug --dry-run
  

Install chart with command:

• For HTTPS repository

  helm install vmd vm/victoria-metrics-distributed -f values.yaml -n NAMESPACE
  

• For OCI repository

  helm install vmd oci://ghcr.io/victoriametrics/helm-charts/victoria-metrics-distributed -f values.yaml -n NAMESPACE
  

Get the pods lists by running this commands:

kubectl get pods -A | grep 'vmd'

Get the application by running this command:

helm list -f vmd -n NAMESPACE

See the history of versions of vmd application with command.

helm history vmd -n NAMESPACE

How to upgrade #

In order to serving query and ingestion while upgrading components version or changing configurations, it’s recommended to perform maintenance on availability zone one by one. First, performing update on availability zone zone-eu-1:

1. remove zone-eu-1 from serving query by setting .Values.availabilityZones.{zone-eu-1}.read.allow=false;
2. run helm upgrade vm-dis -n NAMESPACE with updated configurations for zone-eu-1 in values.yaml;
3. wait for all the components on zone zone-eu-1 running;
4. wait zone-us-1 vmagent persistent queue for zone-eu-1 been drained, add zone-eu-1 back to serving query by setting .Values.availabilityZones.{zone-eu-1}.read.allow=true.

Then, perform update on availability zone zone-us-1 with the same steps1~4.

Upgrade to 0.5.0 #

This release was refactored, names of the parameters was changed:

• vmauthIngestGlobal was changed to write.global.vmauth
• vmauthQueryGlobal was changed to read.global.vmauth
• availabilityZones[*].allowIngest was changed to availabilityZones[*].write.allow
• availabilityZones[*].allowRead was changed to availabilityZones[*].read.allow
• availabilityZones[*].nodeSelector was moved to availabilityZones[*].common.spec.nodeSelector
• availabilityZones[*].extraAffinity was moved to availabilityZones[*].common.spec.affinity
• availabilityZones[*].topologySpreadConstraints was moved to availabilityZones[*].common.spec.topologySpreadConstraints
• availabilityZones[*].vmauthIngest was moved to availabilityZones[*].write.vmauth
• availabilityZones[*].vmauthQueryPerZone was moved to availabilityZones[*].read.perZone.vmauth
• availabilityZones[*].vmauthCrossAZQuery was moved to availabilityZones[*].read.crossZone.vmauth

Example:

If before an upgrade you had given below configuration

vmauthIngestGlobal:
  spec:
    extraArgs:
      discoverBackendIPs: "true"
vmauthQueryGlobal:
  spec:
    extraArgs:
      discoverBackendIPs: "true"
availabilityZones:
  - name: zone-eu-1
    vmauthIngest:
      spec:
        extraArgs:
          discoverBackendIPs: "true"
    vmcluster:
      spec:
        retentionPeriod: "14"

after upgrade it will look like this:

write:
  global:
    vmauth:
      spec:
        extraArgs:
          discoverBackendIPs: "true"
read:
  global:
    vmauth:
      spec:
        extraArgs:
          discoverBackendIPs: "true"
availabilityZones:
  - name: zone-eu-1
    write:
      vmauth:
        spec:
          extraArgs:
            discoverBackendIPs: "true"
    vmcluster:
      spec:
        retentionPeriod: "14"

How to uninstall #

Remove application with command.

helm uninstall vmd -n NAMESPACE

Documentation of Helm Chart #

Install helm-docs following the instructions on this tutorial.

Generate docs with helm-docs command.

cd charts/victoria-metrics-distributed

helm-docs

The markdown generation is entirely go template driven. The tool parses metadata from charts and generates a number of sub-templates that can be referenced in a template file (by default README.md.gotmpl). If no template file is provided, the tool has a default internal template that will generate a reasonably formatted README.

Parameters #

The following tables lists the configurable parameters of the chart and their default values.

Change the values according to the need of the environment in victoria-metrics-distributed`/values.yaml file.

- name: zone-eu-1
- name: zone-us-1

zone-eu-1

zone-us-1

port: "8429"

"8427"

vminsert:
    port: "8480"
    serviceSpec:
        spec:
            clusterIP: None
            type: ClusterIP
vmselect:
    port: "8481"

false

vmagent:
    enabled: true
    name: test-vmagent
    spec:
        selectAllByDefault: true

""

cluster:
    dnsDomain: cluster.local.

cluster.local.

vm-distributed

true

vmauth-global-read-{{ .fullname }}

{}

alertmanager:
    enabled: false
enabled: true
grafana:
    enabled: true
victoria-metrics-operator:
    enabled: true
vmagent:
    enabled: false
vmalert:
    enabled: false
vmcluster:
    enabled: false
vmsingle:
    enabled: false

true

vmauth-global-write-{{ .fullname }}

{}

common:
    spec:
        affinity: {}
        nodeSelector:
            topology.kubernetes.io/zone: '{{ (.zone).name }}'
        topologySpreadConstraints:
            - maxSkew: 1
              topologyKey: kubernetes.io/hostname
              whenUnsatisfiable: ScheduleAnyway
read:
    allow: true
    crossZone:
        vmauth:
            enabled: true
            name: vmauth-read-proxy-{{ (.zone).name }}
            spec: {}
    perZone:
        vmauth:
            enabled: true
            name: vmauth-read-balancer-{{ (.zone).name }}
            spec:
                extraArgs:
                    discoverBackendIPs: "true"
vmagent:
    annotations: {}
    enabled: true
    name: vmagent-{{ (.zone).name }}
    spec: {}
vmcluster:
    enabled: true
    name: vmcluster-{{ (.zone).name }}
    spec:
        replicationFactor: 2
        retentionPeriod: "14"
        vminsert:
            extraArgs: {}
            replicaCount: 2
            resources: {}
        vmselect:
            extraArgs: {}
            replicaCount: 2
            resources: {}
        vmstorage:
            replicaCount: 2
            resources: {}
            storageDataPath: /vm-data
write:
    allow: true
    vmauth:
        enabled: true
        name: vmauth-write-balancer-{{ (.zone).name }}
        spec:
            extraArgs:
                discoverBackendIPs: "true"

affinity: {}
nodeSelector:
    topology.kubernetes.io/zone: '{{ (.zone).name }}'
topologySpreadConstraints:
    - maxSkew: 1
      topologyKey: kubernetes.io/hostname
      whenUnsatisfiable: ScheduleAnyway

true

true

vmauth-read-proxy-{{ (.zone).name }}

{}

true

vmauth-read-balancer-{{ (.zone).name }}

extraArgs:
    discoverBackendIPs: "true"

{}

true

vmagent-{{ (.zone).name }}

{}

true

vmcluster-{{ (.zone).name }}

replicationFactor: 2
retentionPeriod: "14"
vminsert:
    extraArgs: {}
    replicaCount: 2
    resources: {}
vmselect:
    extraArgs: {}
    replicaCount: 2
    resources: {}
vmstorage:
    replicaCount: 2
    resources: {}
    storageDataPath: /vm-data

true

true

vmauth-write-balancer-{{ (.zone).name }}

extraArgs:
    discoverBackendIPs: "true"