79 lines
2.5 KiB
Markdown
79 lines
2.5 KiB
Markdown
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# High Availability
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To gain a higher level of availability for your Instance, you can
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- create more Kubernetes Cluster Nodes
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- create more replicas of the *nscale* and *nplus* components
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- distribute those replicas across multiple nodes using anti-affinities
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This is how:
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```
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helm install \
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--values samples/ha/values.yaml
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--values samples/environment/demo.yaml \
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sample-ha nplus/nplus-instance
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```
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The essents of the values file is this:
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- We use three (3) *nscale Server Application Layer*, two dedicated to user access, one dedicated to jobs
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- if the jobs node fails, the user nodes take the jobs (handled by priority)
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- if one of the user nodes fail, the other one handles the load
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- Kubernetes takes care of restarting nodes should that happen
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- All components run with two replicas
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- Pod anti-affinities handle the distribution
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- any administration component only connects to the jobs nappl, leaving the user nodes to the users
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- PodDisruptionBudgets are defined for the crutial components. These are set via `minReplicaCount` for the components that can support multiple replicas, and `minReplicaCountType` for the **first** replicaSet of the components that do not support replicas, in this case nstla.
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```
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web:
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replicaCount: 2
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minReplicaCount: 1
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rs:
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replicaCount: 2
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minReplicaCount: 1
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ilm:
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replicaCount: 2
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minReplicaCount: 1
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cmis:
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replicaCount: 2
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minReplicaCount: 1
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webdav:
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replicaCount: 2
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minReplicaCount: 1
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nstla:
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minReplicaCountType: 1
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administrator:
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nappl:
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host: "{{ .component.prefix }}nappljobs.{{ .Release.Namespace }}"
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waitFor:
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- "-service {{ .component.prefix }}nappljobs.{{ .Release.Namespace }}.svc.cluster.local:{{ .this.nappl.port }} -timeout 600"
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pam:
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nappl:
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host: "{{ .component.prefix }}nappljobs.{{ .Release.Namespace }}"
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waitFor:
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- "-service {{ .component.prefix }}nappljobs.{{ .Release.Namespace }}.svc.cluster.local:{{ .this.nappl.port }} -timeout 600"
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nappl:
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replicaCount: 2
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minReplicaCount: 1
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jobs: false
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waitFor:
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- "-service {{ .component.prefix }}nappljobs.{{ .Release.Namespace }}.svc.cluster.local:{{ .this.nappl.port }} -timeout 600"
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nappljobs:
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replicaCount: 1
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jobs: true
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disableSessionReplication: true
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ingress:
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enabled: false
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snc:
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enabled: true
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waitFor:
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- "-service {{ .component.prefix }}database.{{ .Release.Namespace }}.svc.cluster.local:5432 -timeout 600"
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application:
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nstl:
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host: "{{ .component.prefix }}nstl-cluster.{{ .Release.Namespace }}"
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nappl:
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host: "{{ .component.prefix }}nappljobs.{{ .Release.Namespace }}"
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```
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