$ cat kafka-user-template.yaml
apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaUser
metadata: 
  labels: 
    strimzi.io/cluster: user-cluster-name
  name: my-user-000
  namespace: user-cluster-test
spec: 
  authentication: 
    type: scram-sha-512
status: 
  secret: my-user-000
  username: my-user-000

# Create users
for i in $(seq 0 99); do cp kafka-user-template.yaml kafkauser-$(printf "%.3d\n" $i).yaml; done;

# make correct numbers in files
for i in $(seq 0 99); do gsed -i "/000/s/000/$(printf "%.3d\n" $i)/" kafkauser-$(printf "%.3d\n" $i).yaml; done;

# Create users, wait for ready state after creation
for i in $(seq 0 99); do 
  number=$(printf "%.3d\n" $i);
  kubectl apply -f kafkauser-$number.yaml -n user-cluster-test;
  kubectl wait --for=condition=ready kafkauser/my-user-$number -n user-cluster-test;
done;

# Teardown
for i in $(seq 0 99); do 
  number=$(printf "%.3d\n" $i);
  kubectl delete -f kafkauser-$number.yaml -n user-cluster-test;
done;

2021-09-13 10:22:46 DEBUG NetworkClient:880 - [AdminClient clientId=adminclient-1] Received DESCRIBE_CLIENT_QUOTAS response from node 0 for request with header RequestHeader(apiKey=DESCRIBE_CLIENT_QUOTAS, apiVersion=1, clientId=adminclient-1, correlationId=3089): DescribeClientQuotasResponseData(throttleTimeMs=0, errorCode=0, errorMessage='', entries=[])
2021-09-13 10:22:46 DEBUG KafkaAdminClient:1099 - [AdminClient clientId=adminclient-1] Sending DescribeClientQuotasRequestData(components=[ComponentData(entityType='user', matchType=0, match='CN=my-user-402420895-684675850-11')], strict=false) to user-cluster-name-kafka-0.user-cluster-name-kafka-brokers.user-cluster-test.svc:9091 (id: 0 rack: null). correlationId=3090
2021-09-13 10:22:46 DEBUG NetworkClient:522 - [AdminClient clientId=adminclient-1] Sending DESCRIBE_CLIENT_QUOTAS request with header RequestHeader(apiKey=DESCRIBE_CLIENT_QUOTAS, apiVersion=1, clientId=adminclient-1, correlationId=3090) and timeout 1365 to node 0: DescribeClientQuotasRequestData(components=[ComponentData(entityType='user', matchType=0, match='CN=my-user-402420895-684675850-11')], strict=false)
2021-09-13 10:22:46 DEBUG QuotasOperator:58 - Reconciliation #1115(watch) KafkaUser(user-cluster-test/my-user-402420895-684675850-54): No expected quotas and no existing quotas -> NoOp
2021-09-13 10:22:46 DEBUG KafkaAdminClient:815 - [AdminClient clientId=adminclient-1] Call(callName=alterUserScramCredentials, deadlineMs=1631528566317, tries=1, nextAllowedTryMs=1631528566418) timed out at 1631528566318 after 1 attempt(s)
java.lang.Exception: TimeoutException: Timed out waiting to send the call. Call: alterUserScramCredentials
	at org.apache.kafka.clients.admin.KafkaAdminClient$Call.failWithTimeout(KafkaAdminClient.java:816) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at org.apache.kafka.clients.admin.KafkaAdminClient$Call.fail(KafkaAdminClient.java:789) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at org.apache.kafka.clients.admin.KafkaAdminClient$TimeoutProcessor.handleTimeouts(KafkaAdminClient.java:912) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.timeoutCallsToSend(KafkaAdminClient.java:993) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.processRequests(KafkaAdminClient.java:1301) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.run(KafkaAdminClient.java:1264) [org.apache.kafka.kafka-clients-2.8.0.jar:?]
	at java.lang.Thread.run(Thread.java:829) [?:?]
2021-09-13 10:22:46 DEBUG KafkaAdminClient:997 - [AdminClient clientId=adminclient-1] Timed out 1 call(s) with assigned nodes.
2021-09-13 10:22:46 ERROR AbstractOperator:240 - Reconciliation #1115(watch) KafkaUser(user-cluster-test/my-user-402420895-684675850-54): createOrUpdate failed
org.apache.kafka.common.errors.TimeoutException: Call(callName=alterUserScramCredentials, deadlineMs=1631528566317, tries=1, nextAllowedTryMs=1631528566418) timed out at 1631528566318 after 1 attempt(s)
Caused by: org.apache.kafka.common.errors.TimeoutException: Timed out waiting to send the call. Call: alterUserScramCredentials
2021-09-13 10:22:46 DEBUG CustomResource:172 - Calling CustomResource#setKind doesn't do anything because the Kind is computed and shouldn't be changed
2021-09-13 10:22:46 DEBUG StatusDiff:42 - Ignoring Status diff {"op":"replace","path":"/conditions/0/lastTransitionTime","value":"2021-09-13T10:22:46.318848Z"}
2021-09-13 10:22:46 DEBUG StatusDiff:46 - Status differs: {"op":"replace","path":"/conditions/0/message","value":"Call(callName=alterUserScramCredentials, deadlineMs=1631528566317, tries=1, nextAllowedTryMs=1631528566418) timed out at 1631528566318 after 1 attempt(s)"}