Bug 1826021

```
  export ETCD_DNS_NAME="etcd-0.example.com"
  export ETCD_INITIAL_CLUSTER="etcd-0.example.com=https://etcd-0.example.com:2380,etcd-1.example.com=https://etcd-1.example.com:2380,etcd-2.example.com=https://etcd-2.example.com:2380"
  
  echo "test 1"
  echo ${ETCD_INITIAL_CLUSTER} | grep -oP "(?<=)[^,,\s]*(?==[^=]*${ETCD_DNS_NAME}\b)"
  echo "test 2"
  echo ${ETCD_INITIAL_CLUSTER} | grep -oP "(?<=,)${ETCD_DNS_NAME}(?==)"

test 1
etcd-0.example.com
test 2
``

The function takes the ETCD_DNS_NAME then verifies that it is listed in ETCD_INITIAL_CLUSTER then returns the name in which matches that record. The format for INITIAL_CLUSTER is <name>=<peer-url>. Given that you can see that test 1 matches and test 2 does not. But as Suresh said the issue is not with that function.


> Error: snapshot restore requires exactly one argument

The following example would show how the error could happen. The command `etcdctl snapshot restore` takes a single argument with is $SNAPSHOT_FILE[1]. Notice space in path.

SNAPSHOT_FILE="/home/core/assets/backup dir/snapshot.db"

etcdctl snapshot restore $SNAPSHOT_FILE
Error: snapshot restore requires exactly one argument

Can you confirm your ocp version?


[1]https://github.com/openshift/machine-config-operator/blob/release-4.3/templates/master/00-master/_base/files/usr-local-bin-openshift-recovery-tools-sh.yaml#L186

I will take the same test from c#7 and set ETCD_DNS_NAME=etcd-1.example.com. The command output is shared below and demonstrates the problem that customers have run into when following our docs [1]. The multiple output in "test 1" is passed to the snapshot restore command, resulting in the "snapshot restore requires exactly one argument"

Perhaps my assumption that someone would be configuring ETCD_DNS_NAME and ETCD_INITIAL_CLUSTER in this way is not acceptable. Can you please verify and I will file a documentation bug if needed?


```
export ETCD_DNS_NAME="etcd-1.example.com"
export ETCD_INITIAL_CLUSTER="etcd-0.example.com=https://etcd-0.example.com:2380,etcd-1.example.com=https://etcd-1.example.com:2380,etcd-2.example.com=https://etcd-2.example.com:2380"
  
echo "test 1"
echo ${ETCD_INITIAL_CLUSTER} | grep -oP "(?<=)[^,,\s]*(?==[^=]*${ETCD_DNS_NAME}\b)"
echo "test 2"
echo ${ETCD_INITIAL_CLUSTER} | grep -oP "(?<=,)${ETCD_DNS_NAME}(?==)"


test 1
etcd-0.example.com
etcd-1.example.com
test 2
etcd-1.example.com
```

References:
[1] https://docs.openshift.com/container-platform/4.3/backup_and_restore/disaster_recovery/scenario-2-restoring-cluster-state.html#dr-restoring-cluster-state

I’m adding UpcomingSprint, because I was occupied by fixing bugs with higher priority/severity, developing new features with higher priority, or developing new features to improve stability at a macro level. I will revisit this bug next sprint.

This is a 4.3 bug, and the bug no longer exists in 4.4 and 4.4+. Please don't change the target release. The fix is available and being reviewed:

https://github.com/openshift/machine-config-operator/pull/1913

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (OpenShift Container Platform 4.3.31 bug fix update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:3180