$ oc get etcd -o=jsonpath='{range .items[0].status.conditions[?(@.type=="etcdMembersAvailable")]}{.message}{"\n"}'
This document describes the process to replace a single unhealthy etcd member.
This process depends on whether the etcd member is unhealthy because the machine is not running or the node is not ready, or whether it is unhealthy because the etcd pod is crashlooping.
If you have lost the majority of your master hosts, leading to etcd quorum loss, then you must follow the disaster recovery procedure to restore to a previous cluster state instead of this procedure. If the control plane certificates are not valid on the member being replaced, then you must follow the procedure to recover from expired control plane certificates instead of this procedure. If a master node is lost and a new one is created, the etcd cluster Operator handles generating the new TLS certificates and adding the node as an etcd member. |
Take an etcd backup prior to replacing an unhealthy etcd member.
You can identify if your cluster has an unhealthy etcd member.
Access to the cluster as a user with the cluster-admin
role.
Check the status of the etcdMembersAvailable
status condition using the following command:
$ oc get etcd -o=jsonpath='{range .items[0].status.conditions[?(@.type=="etcdMembersAvailable")]}{.message}{"\n"}'
Review the output:
2 of 3 members are available, ip-10-0-131-183.ec2.internal is unhealthy
This example output shows that the ip-10-0-131-183.ec2.internal
etcd member is unhealthy.
The steps to replace an unhealthy etcd member depend on which of the following states your etcd member is in:
The machine is not running or the node is not ready
The etcd pod is crashlooping
This procedure determines which state your etcd member is in. This enables you to know which procedure to follow to replace the unhealthy etcd member.
If you are aware that the machine is not running or the node is not ready, but you expect it to return to a healthy state soon, then you do not need to perform a procedure to replace the etcd member. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state. |
You have access to the cluster as a user with the cluster-admin
role.
You have identified an unhealthy etcd member.
Determine if the machine is not running:
$ oc get machines -A -ojsonpath='{range .items[*]}{@.status.nodeRef.name}{"\t"}{@.status.providerStatus.instanceState}{"\n"}' | grep -v running
ip-10-0-131-183.ec2.internal stopped (1)
1 | This output lists the node and the status of the node’s machine. If the status is anything other than running , then the machine is not running. |
If the machine is not running, then follow the Replacing an unhealthy etcd member whose machine is not running or whose node is not ready procedure.
Determine if the node is not ready.
If either of the following scenarios are true, then the node is not ready.
If the machine is running, then check whether the node is unreachable:
$ oc get nodes -o jsonpath='{range .items[*]}{"\n"}{.metadata.name}{"\t"}{range .spec.taints[*]}{.key}{" "}' | grep unreachable
ip-10-0-131-183.ec2.internal node-role.kubernetes.io/master node.kubernetes.io/unreachable node.kubernetes.io/unreachable (1)
1 | If the node is listed with an unreachable taint, then the node is not ready. |
If the node is still reachable, then check whether the node is listed as NotReady
:
$ oc get nodes -l node-role.kubernetes.io/master | grep "NotReady"
ip-10-0-131-183.ec2.internal NotReady master 122m v1.18.3 (1)
1 | If the node is listed as NotReady , then the node is not ready. |
If the node is not ready, then follow the Replacing an unhealthy etcd member whose machine is not running or whose node is not ready procedure.
Determine if the etcd pod is crashlooping.
If the machine is running and the node is ready, then check whether the etcd pod is crashlooping.
Verify that all master nodes are listed as Ready
:
$ oc get nodes -l node-role.kubernetes.io/master
NAME STATUS ROLES AGE VERSION
ip-10-0-131-183.ec2.internal Ready master 6h13m v1.18.3
ip-10-0-164-97.ec2.internal Ready master 6h13m v1.18.3
ip-10-0-154-204.ec2.internal Ready master 6h13m v1.18.3
Check whether the status of an etcd pod is either Error
or CrashloopBackoff
:
$ oc get pods -n openshift-etcd | grep etcd
etcd-ip-10-0-131-183.ec2.internal 2/3 Error 7 6h9m (1)
etcd-ip-10-0-164-97.ec2.internal 3/3 Running 0 6h6m
etcd-ip-10-0-154-204.ec2.internal 3/3 Running 0 6h6m
1 | Since this status of this pod is Error , then the etcd pod is crashlooping. |
If the etcd pod is crashlooping, then follow the Replacing an unhealthy etcd member whose etcd pod is crashlooping procedure.
Depending on the state of your unhealthy etcd member, use one of the following procedures:
This procedure details the steps to replace an etcd member that is unhealthy either because the machine is not running or because the node is not ready.
You have identified the unhealthy etcd member.
You have verified that either the machine is not running or the node is not ready.
You have access to the cluster as a user with the cluster-admin
role.
You have taken an etcd backup.
It is important to take an etcd backup before performing this procedure so that your cluster can be restored if you encounter any issues. |
Remove the unhealthy member.
Choose a pod that is not on the affected node:
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc get pods -n openshift-etcd | grep etcd
etcd-ip-10-0-131-183.ec2.internal 3/3 Running 0 123m
etcd-ip-10-0-164-97.ec2.internal 3/3 Running 0 123m
etcd-ip-10-0-154-204.ec2.internal 3/3 Running 0 124m
Connect to the running etcd container, passing in the name of a pod that is not on the affected node:
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
View the member list:
sh-4.2# etcdctl member list -w table
+------------------+---------+------------------------------+---------------------------+---------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+------------------------------+---------------------------+---------------------------+
| 6fc1e7c9db35841d | started | ip-10-0-131-183.ec2.internal | https://10.0.131.183:2380 | https://10.0.131.183:2379 |
| 757b6793e2408b6c | started | ip-10-0-164-97.ec2.internal | https://10.0.164.97:2380 | https://10.0.164.97:2379 |
| ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
+------------------+---------+------------------------------+---------------------------+---------------------------+
Take note of the ID and the name of the unhealthy etcd member, because these values are needed later in the procedure.
Remove the unhealthy etcd member by providing the ID to the etcdctl member remove
command:
sh-4.2# etcdctl member remove 6fc1e7c9db35841d
Member 6fc1e7c9db35841d removed from cluster baa565c8919b060e
View the member list again and verify that the member was removed:
sh-4.2# etcdctl member list -w table
+------------------+---------+------------------------------+---------------------------+---------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+------------------------------+---------------------------+---------------------------+
| 757b6793e2408b6c | started | ip-10-0-164-97.ec2.internal | https://10.0.164.97:2380 | https://10.0.164.97:2379 |
| ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
+------------------+---------+------------------------------+---------------------------+---------------------------+
You can now exit the node shell.
Remove the old secrets for the unhealthy etcd member that was removed.
List the secrets for the unhealthy etcd member that was removed.
$ oc get secrets -n openshift-etcd | grep ip-10-0-131-183.ec2.internal (1)
1 | Pass in the name of the unhealthy etcd member that you took note of earlier in this procedure. |
There is a peer, serving, and metrics secret as shown in the following output:
etcd-peer-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
etcd-serving-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
etcd-serving-metrics-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
Delete the secrets for the unhealthy etcd member that was removed.
Delete the peer secret:
$ oc delete secret -n openshift-etcd etcd-peer-ip-10-0-131-183.ec2.internal
Delete the serving secret:
$ oc delete secret -n openshift-etcd etcd-serving-ip-10-0-131-183.ec2.internal
Delete the metrics secret:
$ oc delete secret -n openshift-etcd etcd-serving-metrics-ip-10-0-131-183.ec2.internal
Delete and recreate the master machine. After this machine is recreated, a new revision is forced and etcd scales up automatically.
If you are running installer-provisioned infrastructure, or you used the Machine API to create your machines, follow these steps. Otherwise, you must create the new master using the same method that was used to originally create it.
Obtain the machine for the unhealthy member.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc get machines -n openshift-machine-api -o wide
NAME PHASE TYPE REGION ZONE AGE NODE PROVIDERID STATE
clustername-8qw5l-master-0 Running m4.xlarge us-east-1 us-east-1a 3h37m ip-10-0-131-183.ec2.internal aws:///us-east-1a/i-0ec2782f8287dfb7e stopped (1)
clustername-8qw5l-master-1 Running m4.xlarge us-east-1 us-east-1b 3h37m ip-10-0-154-204.ec2.internal aws:///us-east-1b/i-096c349b700a19631 running
clustername-8qw5l-master-2 Running m4.xlarge us-east-1 us-east-1c 3h37m ip-10-0-164-97.ec2.internal aws:///us-east-1c/i-02626f1dba9ed5bba running
clustername-8qw5l-worker-us-east-1a-wbtgd Running m4.large us-east-1 us-east-1a 3h28m ip-10-0-129-226.ec2.internal aws:///us-east-1a/i-010ef6279b4662ced running
clustername-8qw5l-worker-us-east-1b-lrdxb Running m4.large us-east-1 us-east-1b 3h28m ip-10-0-144-248.ec2.internal aws:///us-east-1b/i-0cb45ac45a166173b running
clustername-8qw5l-worker-us-east-1c-pkg26 Running m4.large us-east-1 us-east-1c 3h28m ip-10-0-170-181.ec2.internal aws:///us-east-1c/i-06861c00007751b0a running
1 | This is the master machine for the unhealthy node, ip-10-0-131-183.ec2.internal . |
Save the machine configuration to a file on your file system:
$ oc get machine clustername-8qw5l-master-0 \ (1)
-n openshift-machine-api \
-o yaml \
> new-master-machine.yaml
1 | Specify the name of the master machine for the unhealthy node. |
Edit the new-master-machine.yaml
file that was created in the previous step to assign a new name and remove unnecessary fields.
Remove the entire status
section:
status:
addresses:
- address: 10.0.131.183
type: InternalIP
- address: ip-10-0-131-183.ec2.internal
type: InternalDNS
- address: ip-10-0-131-183.ec2.internal
type: Hostname
lastUpdated: "2020-04-20T17:44:29Z"
nodeRef:
kind: Node
name: ip-10-0-131-183.ec2.internal
uid: acca4411-af0d-4387-b73e-52b2484295ad
phase: Running
providerStatus:
apiVersion: awsproviderconfig.openshift.io/v1beta1
conditions:
- lastProbeTime: "2020-04-20T16:53:50Z"
lastTransitionTime: "2020-04-20T16:53:50Z"
message: machine successfully created
reason: MachineCreationSucceeded
status: "True"
type: MachineCreation
instanceId: i-0fdb85790d76d0c3f
instanceState: stopped
kind: AWSMachineProviderStatus
Change the metadata.name
field to a new name.
It is recommended to keep the same base name as the old machine and change the ending number to the next available number. In this example, clustername-8qw5l-master-0
is changed to clustername-8qw5l-master-3
.
For example:
apiVersion: machine.openshift.io/v1beta1
kind: Machine
metadata:
...
name: clustername-8qw5l-master-3
...
Update the metadata.selfLink
field to use the new machine name from the previous step.
apiVersion: machine.openshift.io/v1beta1
kind: Machine
metadata:
...
selfLink: /apis/machine.openshift.io/v1beta1/namespaces/openshift-machine-api/machines/clustername-8qw5l-master-3
...
Remove the spec.providerID
field:
providerID: aws:///us-east-1a/i-0fdb85790d76d0c3f
Remove the metadata.annotations
and metadata.generation
fields:
annotations:
machine.openshift.io/instance-state: running
...
generation: 2
Remove the metadata.resourceVersion
and metadata.uid
fields:
resourceVersion: "13291"
uid: a282eb70-40a2-4e89-8009-d05dd420d31a
Delete the machine of the unhealthy member:
$ oc delete machine -n openshift-machine-api clustername-8qw5l-master-0 (1)
1 | Specify the name of the master machine for the unhealthy node. |
Verify that the machine was deleted:
$ oc get machines -n openshift-machine-api -o wide
NAME PHASE TYPE REGION ZONE AGE NODE PROVIDERID STATE
clustername-8qw5l-master-1 Running m4.xlarge us-east-1 us-east-1b 3h37m ip-10-0-154-204.ec2.internal aws:///us-east-1b/i-096c349b700a19631 running
clustername-8qw5l-master-2 Running m4.xlarge us-east-1 us-east-1c 3h37m ip-10-0-164-97.ec2.internal aws:///us-east-1c/i-02626f1dba9ed5bba running
clustername-8qw5l-worker-us-east-1a-wbtgd Running m4.large us-east-1 us-east-1a 3h28m ip-10-0-129-226.ec2.internal aws:///us-east-1a/i-010ef6279b4662ced running
clustername-8qw5l-worker-us-east-1b-lrdxb Running m4.large us-east-1 us-east-1b 3h28m ip-10-0-144-248.ec2.internal aws:///us-east-1b/i-0cb45ac45a166173b running
clustername-8qw5l-worker-us-east-1c-pkg26 Running m4.large us-east-1 us-east-1c 3h28m ip-10-0-170-181.ec2.internal aws:///us-east-1c/i-06861c00007751b0a running
Create the new machine using the new-master-machine.yaml
file:
$ oc apply -f new-master-machine.yaml
Verify that the new machine has been created:
$ oc get machines -n openshift-machine-api -o wide
NAME PHASE TYPE REGION ZONE AGE NODE PROVIDERID STATE
clustername-8qw5l-master-1 Running m4.xlarge us-east-1 us-east-1b 3h37m ip-10-0-154-204.ec2.internal aws:///us-east-1b/i-096c349b700a19631 running
clustername-8qw5l-master-2 Running m4.xlarge us-east-1 us-east-1c 3h37m ip-10-0-164-97.ec2.internal aws:///us-east-1c/i-02626f1dba9ed5bba running
clustername-8qw5l-master-3 Provisioning m4.xlarge us-east-1 us-east-1a 85s ip-10-0-133-53.ec2.internal aws:///us-east-1a/i-015b0888fe17bc2c8 running (1)
clustername-8qw5l-worker-us-east-1a-wbtgd Running m4.large us-east-1 us-east-1a 3h28m ip-10-0-129-226.ec2.internal aws:///us-east-1a/i-010ef6279b4662ced running
clustername-8qw5l-worker-us-east-1b-lrdxb Running m4.large us-east-1 us-east-1b 3h28m ip-10-0-144-248.ec2.internal aws:///us-east-1b/i-0cb45ac45a166173b running
clustername-8qw5l-worker-us-east-1c-pkg26 Running m4.large us-east-1 us-east-1c 3h28m ip-10-0-170-181.ec2.internal aws:///us-east-1c/i-06861c00007751b0a running
1 | The new machine, clustername-8qw5l-master-3 is being created and is ready once the phase changes from Provisioning to Running . |
It might take a few minutes for the new machine to be created. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.
Verify that all etcd pods are running properly.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc get pods -n openshift-etcd | grep etcd
etcd-ip-10-0-133-53.ec2.internal 3/3 Running 0 7m49s
etcd-ip-10-0-164-97.ec2.internal 3/3 Running 0 123m
etcd-ip-10-0-154-204.ec2.internal 3/3 Running 0 124m
If the output from the previous command only lists two pods, you can manually force an etcd redeployment. In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge (1)
1 | The forceRedeploymentReason value must be unique, which is why a timestamp is appended. |
Verify that there are exactly three etcd members.
Connect to the running etcd container, passing in the name of a pod that was not on the affected node:
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
View the member list:
sh-4.2# etcdctl member list -w table
+------------------+---------+------------------------------+---------------------------+---------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+------------------------------+---------------------------+---------------------------+
| 5eb0d6b8ca24730c | started | ip-10-0-133-53.ec2.internal | https://10.0.133.53:2380 | https://10.0.133.53:2379 |
| 757b6793e2408b6c | started | ip-10-0-164-97.ec2.internal | https://10.0.164.97:2380 | https://10.0.164.97:2379 |
| ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
+------------------+---------+------------------------------+---------------------------+---------------------------+
If the output from the previous command lists more than three etcd members, you must carefully remove the unwanted member.
Be sure to remove the correct etcd member; removing a good etcd member might lead to quorum loss. |
This procedure details the steps to replace an etcd member that is unhealthy because the etcd pod is crashlooping.
You have identified the unhealthy etcd member.
You have verified that the etcd pod is crashlooping.
You have access to the cluster as a user with the cluster-admin
role.
You have taken an etcd backup.
It is important to take an etcd backup before performing this procedure so that your cluster can be restored if you encounter any issues. |
Stop the crashlooping etcd pod.
Debug the node that is crashlooping.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc debug node/ip-10-0-131-183.ec2.internal (1)
1 | Replace this with the name of the unhealthy node. |
Change your root directory to the host:
sh-4.2# chroot /host
Move the existing etcd pod file out of the kubelet manifest directory:
sh-4.2# mkdir /var/lib/etcd-backup
sh-4.2# mv /etc/kubernetes/manifests/etcd-pod.yaml /var/lib/etcd-backup/
Move the etcd data directory to a different location:
sh-4.2# mv /var/lib/etcd/ /tmp
You can now exit the node shell.
Remove the unhealthy member.
Choose a pod that is not on the affected node.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc get pods -n openshift-etcd | grep etcd
etcd-ip-10-0-131-183.ec2.internal 2/3 Error 7 6h9m
etcd-ip-10-0-164-97.ec2.internal 3/3 Running 0 6h6m
etcd-ip-10-0-154-204.ec2.internal 3/3 Running 0 6h6m
Connect to the running etcd container, passing in the name of a pod that is not on the affected node.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
View the member list:
sh-4.2# etcdctl member list -w table
+------------------+---------+------------------------------+---------------------------+---------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+------------------------------+---------------------------+---------------------------+
| 62bcf33650a7170a | started | ip-10-0-131-183.ec2.internal | https://10.0.131.183:2380 | https://10.0.131.183:2379 |
| b78e2856655bc2eb | started | ip-10-0-164-97.ec2.internal | https://10.0.164.97:2380 | https://10.0.164.97:2379 |
| d022e10b498760d5 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
+------------------+---------+------------------------------+---------------------------+---------------------------+
Take note of the ID and the name of the unhealthy etcd member, because these values are needed later in the procedure.
Remove the unhealthy etcd member by providing the ID to the etcdctl member remove
command:
sh-4.2# etcdctl member remove 62bcf33650a7170a
Member 62bcf33650a7170a removed from cluster ead669ce1fbfb346
View the member list again and verify that the member was removed:
sh-4.2# etcdctl member list -w table
+------------------+---------+------------------------------+---------------------------+---------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+------------------------------+---------------------------+---------------------------+
| b78e2856655bc2eb | started | ip-10-0-164-97.ec2.internal | https://10.0.164.97:2380 | https://10.0.164.97:2379 |
| d022e10b498760d5 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
+------------------+---------+------------------------------+---------------------------+---------------------------+
You can now exit the node shell.
Remove the old secrets for the unhealthy etcd member that was removed.
List the secrets for the unhealthy etcd member that was removed.
$ oc get secrets -n openshift-etcd | grep ip-10-0-131-183.ec2.internal (1)
1 | Pass in the name of the unhealthy etcd member that you took note of earlier in this procedure. |
There is a peer, serving, and metrics secret as shown in the following output:
etcd-peer-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
etcd-serving-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
etcd-serving-metrics-ip-10-0-131-183.ec2.internal kubernetes.io/tls 2 47m
Delete the secrets for the unhealthy etcd member that was removed.
Delete the peer secret:
$ oc delete secret -n openshift-etcd etcd-peer-ip-10-0-131-183.ec2.internal
Delete the serving secret:
$ oc delete secret -n openshift-etcd etcd-serving-ip-10-0-131-183.ec2.internal
Delete the metrics secret:
$ oc delete secret -n openshift-etcd etcd-serving-metrics-ip-10-0-131-183.ec2.internal
Force etcd redeployment.
In a terminal that has access to the cluster as a cluster-admin
user, run the following command:
$ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "single-master-recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge (1)
1 | The forceRedeploymentReason value must be unique, which is why a timestamp is appended. |
When the etcd cluster Operator performs a redeployment, it ensures that all master nodes have a functioning etcd pod.
Verify that the new member is available and healthy.
Connect to the running etcd container again.
In a terminal that has access to the cluster as a cluster-admin user, run the following command:
$ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
Verify that all members are healthy:
sh-4.2# etcdctl endpoint health --cluster
https://10.0.131.183:2379 is healthy: successfully committed proposal: took = 16.671434ms
https://10.0.154.204:2379 is healthy: successfully committed proposal: took = 16.698331ms
https://10.0.164.97:2379 is healthy: successfully committed proposal: took = 16.621645ms