General questions about Managed Service for Apache Kafka®

• How do I ensure my cluster is fault tolerant?

• What do I do if I get an error like "disk size must be at least ... according to topics partitions number and replication factor, but size is ..."?

• How do I get the logs of my actions in the services?

• How do I move a cluster to a different network?

• How do I set up an alert that triggers as soon as a certain percentage of disk space has been used up?

• Why is the cluster slow even though the computing resources are not used fully?

• Can I connect to cluster hosts via SSH or get superuser permissions on hosts?

• What do I do if I get the revocation check error when using PowerShell to obtain an SSL certificate?

How do I ensure my cluster is fault tolerant?How do I ensure my cluster is fault tolerant?

Make sure it meets all fault tolerance conditions.

What do I do if I get an error like "disk size must be at least ... according to topics partitions number and replication factor, but size is ..."?What do I do if I get an error like "disk size must be at least ... according to topics partitions number and replication factor, but size is ..."?

The error results from the fact that your topics' log segments take up more space than is available in broker storage. For more information about calculating the required space, see Minimum storage size.

To solve the issue, you can increase the disk size or reduce the topic segment or total cluster size.

Can I get logs of my operations with services?Can I get logs of my operations with services?

Yes, you can request log records about your resources from Yandex Cloud services. For more information, see Data requests.

What is the retention period for logs?What is the retention period for logs?

Cluster logs are stored for 30 days.

How do I move a cluster to a different network?How do I move a cluster to a different network?

You cannot move a Managed Service for Apache Kafka® cluster to another network.

Here is an alternative solution:

1. Create a new cluster with the same configuration in the target network.
2. Use MirrorMaker to move the topics of the source cluster to the new one.

How do I set up an alert that triggers as soon as a certain percentage of disk space has been used up?How do I set up an alert that triggers as soon as a certain percentage of disk space has been used up?

Create an alert with the disk.used_bytes metric in Yandex Monitoring. This metric shows the disk space usage in the Managed Service for Apache Kafka® cluster.

For disk.used_bytes, use notification thresholds. The recommended values are as follows:

• Alarm: 90% of the disk space
• Warning: 80% of the disk space

Thresholds are set in bytes only. For example, the recommended values for a 100 GB disk are as follows:

• Alarm: 96636764160 bytes (90%)
• Warning: 85899345920 bytes (80%)

Why is the cluster slow even though the computing resources are not used fully?Why is the cluster slow even though the computing resources are not used fully?

Perhaps, the maximum storage IOPS and bandwidth values are insufficient for processing the current number of requests. In this case, throttling is triggered and the performance of the entire cluster degrades.

The maximum IOPS and bandwidth values increase by a fixed value when the storage size increases by a certain step. The step and increment values depend on the disk type:

To increase the maximum IOPS and bandwidth values and make throttling less likely, increase the storage size.

Can I connect to cluster hosts via SSH or get superuser permissions on hosts?Can I connect to cluster hosts via SSH or get superuser permissions on hosts?

You cannot connect to hosts via SSH. This is done for the sake of security and user cluster fault tolerance because direct changes inside a host can render it completely inoperable.

What do I do if I get the revocation check error when using PowerShell to obtain an SSL certificate?What do I do if I get the revocation check error when using PowerShell to obtain an SSL certificate?

Here is the full text of the error:

curl: (35) schannel: next InitializeSecurityContext failed: Unknown error (0x80092012)
The revocation function was unable to check revocation for the certificate

This means, when connecting to the website, the service failed to check whether or not the website’s certificate is on the list of revoked certificates.

To fix this error:

• Make sure the corporate network settings do not block the check.

• Run the command with the --ssl-no-revoke parameter.

  mkdir $HOME\.kafka; curl.exe --ssl-no-revoke -o $HOME\.kafka\YandexInternalRootCA.crt https://storage.yandexcloud.net/cloud-certs/CA.pem