I have a REDIS cluster consisting of 3 masters and 3 slaves. Platform configuration on which REDIS nodes run is such that a node can change IP when it is restarted.
After restart of a node, 5 other nodes correctly update the IP address of restarted node, but that particular node keeps old IP address in its configuration.
What should be made so that the node that has changed the IP updates its configuration?
Related
We want to set up Redis 6.2 clustering behind a LB. There are only master nodes and there is no Redis Sentinel being used. Each cluster-enabled Redis instance is running on a different host with the same configuration (eg. all of them are configured with port 6379). Is this possible with some port configuration on the LB such that a unique port on an LB maps to a unique_ip:6379?
Our idea is to use a cluster-aware Redis client like Lettuce RedisClusterClient which would issue CLUSTER NODES/SLOTS commands or react to MOVED/ASK redirection. It would also take care of split up a pipeline into using separate connections based on the slot for a command
It seems like this is not possible to achieve if the same port is used on all Redis hosts. Using https://docs.redis.com/latest/rs/networking/cluster-lba-setup/ as a guide, the best we could manage was to configure each Redis with a unique port and set cluster-announce-ip as the virtual IP (points to LB) and then manually make sure that the same port is used on LB as the Redis host. With this, the CLUSTER SLOTS and MOVED responses from Redis hosts could be correctly acted upon by the client. But this complicates our setup when a new Redis host has to be added or removed
You can use Route 53 if you're on AWS to achieve this.
Create A setup like this:
Add all hosts(IP addresses) in Route 53 and set TTL to smaller values like 30 seconds or so. Route 53 will return one of these Redis IP addresses, using this endpoint Redis clients like Lettuce or Jedis will discover all the Redis nodes.
You can use any other DNS system as well, record type should be A.
I have to nodes named VMQ1#127.0.0.1 and VMQ2#127.0.0.1 on two different containers in the same virtual machine
but when i try from node2 to join the cluster with vmq-admin as below:
vmq-admin cluster join discovery-node=VMQ1#127.0.0.1.
It says it cannot discover the node or node not found.
Where am i going wrong??
And yes the cookies are set to same variable and all the ports that are need to be opened are exposed.
So I recently installed stable/redis-ha cluster (https://github.com/helm/charts/tree/master/stable/redis-ha) on my G-Cloud based kubernetes cluster. The cluster was installed as a "Headless Service" without a ClusterIP. There are 3 pods that make up this cluster one of which is elected master.
The cluster has installed with no issues and can be accessed via redis-cli from my local pc (after port-forwarding with kubectl).
The output from the cluster install provided me with DNS name for the cluster. Because the service is a headless I am using the following DNS Name
port_name.port_protocol.svc.namespace.svc.cluster.local (As specified by the documentation)
When attempting to connect I get the following error:
"redis.exceptions.ConnectionError: Error -2 connecting to
port_name.port_protocol.svc.namespace.svc.cluster.local :6379. Name does not
resolve."
This is not working.
Not sure what to do here. Any help would be greatly appreciated.
the DNS appears to be incorrect. it should be in the below format
<redis-service-name>.<namespace>.svc.cluster.local:6379
say, redis service name is redis and namespace is default then it should be
redis.default.svc.cluster.local:6379
you can also use pod dns, like below
<redis-pod-name>.<redis-service-name>.<namespace>.svc.cluster.local:6379
say, redis pod name is redis-0 and redis service name is redis and namespace is default then it should be
redis-0.redis.default.svc.cluster.local:6379
assuming the service port is same as container port and that is 6379
Not sure if this is still relevant. Just enhance the chart similar to other charts to support NodePort, e.g. rabbitmq-ha so that you can use any node ip and configured node port if you want to access redis from outside the cluster.
I have a GoogleCloud Kubernetes cluster consisting of multiple nodes and a GoogleCloud Redis Memorystore. Distributed over these nodes are replicas of a pod containing a container that needs to connect to the Redis Memorystore. I have noticed that one of the nodes is not able to connect to Redis, i.e. any container in a pod on that node cannot connect to Redis.
The Redis Memorystore has the following properties:
IP address: 10.0.6.12
Instance IP address range: 10.0.6.8/29 (10.0.6.8 - 10.0.6.15)
The node from which no connection to Redis can be made has the following properties:
Internal IP: 10.132.0.5
PodCIDR: 10.0.6.0/24 (10.0.6.0 - 10.0.6.255)
I assume this problem is caused by the overlap in IP ranges of the Memorystore and this node. Is this assumption correct?
If this is the problem I would like to change the IP range of the node.
I have tried to do this by editing spec.podCIRD in the node config:
$ kubectl edit node <node-name>
However this did not work and resulted in the error message:
# * spec.podCIDR: Forbidden: node updates may not change podCIDR except from "" to valid
# * []: Forbidden: node updates may only change labels, taints, or capacity (or configSource, if the DynamicKubeletConfig feature gate is enabled)
Is there another way to change the IP range of an existing Kubernetes node? If so, how?
Sometimes I need to temporarily increase the number of pods in a cluster. When I do this I want to prevent Kubernetes from creating a new node with the IP range 10.0.6.0/24.
Is it possible to tell the Kubernetes cluster to not create new nodes with the IP range 10.0.6.0/24? If so, how?
Thanks in advance!
Not for a node. The podCidr gets defined when you install your network overlay in initial steps when setting up a new cluster.
Yes for the cluster. but it's not that easy. You have to change the podCidr for the network overlay in your whole cluster. It's a tricky process that can be done, but if you are doing that you might as well deploy a new cluster. Keep in mind that some network overlays require a very specific PodCidr. For example, Calico requires 192.168.0.0/16
You could:
Create a new cluster with a new cidr and move your workloads gradually.
Change the IP address cidr where your GoogleCloud Redis Memorystore lives.
Hope it helps!
I have an issue with the below given statement. I haven't tried executing the statement as I didn't understand what is this used for
What should I pass as arguments for server.1, zoo1
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888
What does the above statement mean
What values should I pass and what is the above statement used for
Can u explain with an example
I have a cluster of 4 computers with high availability enabled
Machine 1 and 2 - Zookeeper, zkfc, Namenode, Resourcemanager, Journal node
Machine3 - Zookepper, Journal node
Machine4 - Datanode
Kindly help
These entries define the quorum of Zookeeper servers.
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888
And they follow the pattern,
server.X=server_name:port1:port2
server.X, where X is the server number in ASCII. Create a file named as myid under the Zookeeper data directory in each Zookeeper server. This file should contain the server number X as an entry in it.
server_name is the hostname of the node where the Zookeeper service is started.
port1, ZooKeeper server uses this port to connect followers to the leader.
port2, this port is used for leader election.
When a new leader arises, a follower opens a TCP connection to the
leader using this port. Because the default leader election also uses
TCP, we currently require another port for leader election. This is
the second port in the server entry.