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Topology spread constraints on zones and anti-affinity for receivers and dispatchers #2092

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merged 2 commits into from
Apr 14, 2022
Merged

Topology spread constraints on zones and anti-affinity for receivers and dispatchers #2092

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Topology spread constraints and anti-affinity for receivers and dispa…
pierDipi Mar 29, 2022
ce1732c
Include sourcev2 dispatcher
pierDipi Apr 13, 2022
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17 changes: 17 additions & 0 deletions data-plane/config/broker/500-dispatcher.yaml
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,23 @@ spec:
app: kafka-broker-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-broker-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-broker-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
Comment on lines +36 to +52
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@aavarghese aavarghese Apr 13, 2022 •
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Do you know if this combination is functionally better than having two pod topology spread constraints - one for zone and one for node? (Was trying to read about this...)

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Since we don't have any specific anti-affinity rules for nodes, we could instead have multiple pod topology spread constraints?

     # To avoid node becoming SPOF, spread our replicas to different nodes and zones.
      topologySpreadConstraints:
        - maxSkew: 2
          topologyKey: topology.kubernetes.io/zone
          whenUnsatisfiable: ScheduleAnyway
          labelSelector:
            matchLabels:
              app: kafka-broker-dispatcher
        - maxSkew: 2
          topologyKey: kubernetes.io/hostname
          whenUnsatisfiable: ScheduleAnyway
          labelSelector:
            matchLabels:
              app: kafka-broker-dispatcher

This should also satisfy the existing anti-affinity rule for preferredDuringSchedulingIgnoredDuringExecution.

On the other hand, our existing dispatchers already had podAntiAffinity for nodes, so if we want to make minimal changes, that is understandable
cc: @pierDipi was this your thinking too?

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Yes, afaik, topologySpreadConstraints + maxSkew = 1 + ScheduleAnyway should be equivalent to our existing antiAffinity rule, I'm ok to migrate antiAffinity rules to use
topologySpreadConstraints + maxSkew = 1 + ScheduleAnyway

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Ok, i think making this equivalent change separately another time/another PR is fine too.

serviceAccountName: knative-kafka-broker-data-plane
securityContext:
runAsNonRoot: true
Expand Down
15 changes: 11 additions & 4 deletions data-plane/config/broker/500-receiver.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,10 +33,14 @@ spec:
app: kafka-broker-receiver
kafka.eventing.knative.dev/release: devel
spec:
serviceAccountName: knative-kafka-broker-data-plane
securityContext:
runAsNonRoot: true
# To avoid node becoming SPOF, spread our replicas to different nodes.
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-broker-receiver
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
Expand All @@ -46,6 +50,9 @@ spec:
app: kafka-broker-receiver
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-broker-data-plane
securityContext:
runAsNonRoot: true
containers:
- name: kafka-broker-receiver
image: ${KNATIVE_KAFKA_RECEIVER_IMAGE}
Expand Down
17 changes: 17 additions & 0 deletions data-plane/config/brokerv2/500-dispatcher.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,23 @@ spec:
app.kubernetes.io/component: kafka-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-broker-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-broker-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-broker-data-plane
securityContext:
runAsNonRoot: true
Expand Down
17 changes: 17 additions & 0 deletions data-plane/config/channel/500-dispatcher.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,23 @@ spec:
app: kafka-channel-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-channel-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-channel-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-channel-data-plane
securityContext:
runAsNonRoot: true
Expand Down
15 changes: 11 additions & 4 deletions data-plane/config/channel/500-receiver.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,10 +33,14 @@ spec:
app: kafka-channel-receiver
kafka.eventing.knative.dev/release: devel
spec:
serviceAccountName: knative-kafka-channel-data-plane
securityContext:
runAsNonRoot: true
# To avoid node becoming SPOF, spread our replicas to different nodes.
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-channel-receiver
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
Expand All @@ -46,6 +50,9 @@ spec:
app: kafka-channel-receiver
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-channel-data-plane
securityContext:
runAsNonRoot: true
containers:
- name: kafka-channel-receiver
image: ${KNATIVE_KAFKA_RECEIVER_IMAGE}
Expand Down
17 changes: 17 additions & 0 deletions data-plane/config/channelv2/500-dispatcher.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,23 @@ spec:
app.kubernetes.io/component: kafka-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-channel-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-channel-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-channel-data-plane
securityContext:
runAsNonRoot: true
Expand Down
15 changes: 11 additions & 4 deletions data-plane/config/sink/500-receiver.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,10 +33,14 @@ spec:
app: kafka-sink-receiver
kafka.eventing.knative.dev/release: devel
spec:
serviceAccountName: knative-kafka-sink-data-plane
securityContext:
runAsNonRoot: true
# To avoid node becoming SPOF, spread our replicas to different nodes.
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-sink-receiver
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
Expand All @@ -46,6 +50,9 @@ spec:
app: kafka-sink-receiver
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-sink-data-plane
securityContext:
runAsNonRoot: true
containers:
- name: kafka-sink-receiver
image: ${KNATIVE_KAFKA_RECEIVER_IMAGE}
Expand Down
17 changes: 17 additions & 0 deletions data-plane/config/source/500-dispatcher.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,23 @@ spec:
app: kafka-source-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-source-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-source-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-source-data-plane
securityContext:
runAsNonRoot: true
Expand Down
17 changes: 17 additions & 0 deletions data-plane/config/sourcev2/500-dispatcher.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,23 @@ spec:
app.kubernetes.io/component: kafka-dispatcher
kafka.eventing.knative.dev/release: devel
spec:
# To avoid node becoming SPOF, spread our replicas to different nodes and zones.
topologySpreadConstraints:
- maxSkew: 2
topologyKey: topology.kubernetes.io/zone
whenUnsatisfiable: ScheduleAnyway
labelSelector:
matchLabels:
app: kafka-source-dispatcher
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app: kafka-source-dispatcher
topologyKey: kubernetes.io/hostname
weight: 100
serviceAccountName: knative-kafka-source-data-plane
securityContext:
runAsNonRoot: true
Expand Down