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Questions tagged [leader-election]

55 questions
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Picking between Redisson and Lettuce for Redis with clustered-setup

I am considering Lettuce and Redisson java clients for use in my application server (to connect to Redis). I haven't been able to find a proper comparison of the two from people who have tried them both or one of them in a single common place. The…
Shabirmean
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3 answers

Why is it recommended to create clusters with odd number of nodes

There are several resources about distributed systems, like the mongo db documentation that recommend odd number of nodes in a cluster. What are the benefits of having odd number of nodes?
ProgramCpp
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4
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1 answer

Why Raft should grant vote when voteFor is candidateId?

I am not sure if I understand the RequestVote RPC detail in Raft correctly. In the paper, it says Receiver implementation: 1. Reply false if term < currentTerm (§5.1) 2. If votedFor is null or candidateId, and candidate’s log is at least as…
pikatao
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1 answer

Understanding etcd Leader election APIs

I am trying to understand various functions provided by etcd election api and what they mean semantically. In their official documentation very briefly mentioned about what each function does, and no examples are provided. For example we have…
greendragons
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3
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3 answers

leader not electing hyperLedger fabric raft ordering service

When i try to deploy fabric-raft ordering service, it shows these logs. it starts election repetitively without electing a leader. i tried changing heartbeat time to 1 sec and election time to 10 sec but that is not working. then i tried to…
xama arshad
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2
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1 answer

Leaderelections failing, lease unable to be renewed automatically

I have a production cluster is currently running on K8s version 1.19.9, where the kube-scheduler and kube-controller-manager failed to have leader elections. The leader is able to acquire the first lease, however it then cannot renew/reacquire the…
janeosaka
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Is there a way to use Kubernetes LeaderElection across multiple clusters?

We are using the native Kubernetes LeaderElection, but it appears to only work within the cluster. Is there a way to make this work across multiple clusters? Official Client:…
Don Rhummy
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How to execute functions once pod is elected leader by using leader-with-lease in operator-framework?

I am trying to run 3 pods/replicas of a container in which I want one of them to be run as the leader and if that particular pod is stopped or fails, immediately the other non-leader running pods should take the leadership to continue execution that…
Yashgiri Goswami
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2
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1 answer

Kubernetes services for all pods and another for only the leader

In Kubernetes, is it possible to have 2 services for a single deployment, one which is "standard" and proxies in front of all ready pods, and a second service which sends traffic only the elected leader? If so how? I am using client-go for leader…
user2133814
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2
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Java leader election using Zookeeper

I read about Java leader election implementation using Zookeeper. I am clear with the algorithm described here. But I have a subtle question to ask about the algorithm. In the algorithm explained, nodes select all the child nodes of the "/election"…
wmIbb
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paxos for system builder

Why a separate phase of Leader Election is required in the paper Paxos for System Builders: An Overview instead of using the prepare phase for the leader election? What advantages does this additional phase provide over using the implicit prepare…
vaibhav
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How to handle loss of Event in Custom Controller in K8s

We have implemented a custom controller in kubernetes, which kind is Pod using the kubebuilder tool. This controller is listening for the Pod event in namespace Queue on pods with label of router. mgr, err :=…
Ashutosh Pandey
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How is Apache Camel making sure there are no two masters?

My starting point is the actually the outbox pattern. To make sure the message in an outbox in only relayed once we only have one replica of the outbox service available in our k8s cluster. To be super sure, the deployment strategy of this service…
Moritz Schmitz v. Hülst
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Is leader election used for active/partial standby use cases for microservice replicas?

For microservice HA, I know there's the "Active/Active" configuration as well as the "Active/Standby" configuration. I'm wondering if you might use Leader Election for something in the middle. For example, say there are 3 microservices which all…
vmayer
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Kubernetes cluster agent: Could not construct reference to ConfigMap

ConfigMap exists in the right namespace, but getting this error that it couldn't construct reference to configmap, and did not get a confirmation that leaderelection has been successfully required. Any advice would be appreciated error log…
yunlee
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