From 944db6d30ea0b9dfcedf1495506fafd014afa28b Mon Sep 17 00:00:00 2001 From: cf250024 <59401847+cf250024@users.noreply.github.com> Date: Fri, 9 Jun 2023 02:55:43 -0700 Subject: [PATCH] Add session affinity FAQ (#299) * Add session affinity FAQ --------- Co-authored-by: Chengjun Fu --- doc/FAQ.md | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/doc/FAQ.md b/doc/FAQ.md index d3c54fd0..f36a05e2 100644 --- a/doc/FAQ.md +++ b/doc/FAQ.md @@ -1,13 +1,17 @@ FAQ - Frequently Asked Questions -====== +================================ Readyness probe fails ---------------- +--------------------- -When encountering errors like `Readiness probe failed: Node not found with CONNECTED state` or `Multi-Attach error for volume "pvc-xxxxxx-xxx-xxx-xxxx-xxxxxxxxx" Volume is already exclusively attached to one node and can't be attached to another`, it means Kubernetes can't provide the pod access to the persistent data it wants. +When encountering errors like `Readiness probe failed: Node not found with CONNECTED state` or `Multi-Attach error for volume "pvc-xxxxxx-xxx-xxx-xxxx-xxxxxxxxx" Volume is already exclusively attached to one node and can't be attached to another`, it means Kubernetes can't provide the pod access to the persistent data it wants. -When this happens, reach out to your Kubernetes cluster administrators to find and fix the problem manually. +When this happens, reach out to your Kubernetes cluster administrators to find and fix the problem manually. For more background, see https://blog.mayadata.io/recover-from-volume-multi-attach-error-in-on-prem-kubernetes-clusters -(see https://github.com/cetic/helm-nifi/issues/47#issuecomment-1122702262) \ No newline at end of file +(see https://github.com/cetic/helm-nifi/issues/47#issuecomment-1122702262) + +## Session Afffinity + +As mentioned in the official NIFI document regarding [session affinity](https://nifi.apache.org/docs/nifi-docs/html/administration-guide.html#session_affinity), it's required to implement this feature for your ingress. Please refer to the ingress controller your are using for how to implement it. One example for GKE is with [issue #271](https://github.com/cetic/helm-nifi/issues/271). If NIFI cluster has more than one node, the session affinity has to be there due to the stateful implementation of each node.