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DBA commands for Azure Managed Instance for Apache Cassandra

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Azure Managed Instance for Apache Cassandra is a fully managed service for pure open-source Apache Cassandra clusters. The service also allows configurations to be overridden, depending on the specific needs of each workload, allowing maximum flexibility and control where needed. This article describes how to run DBA commands manually when the need arises.

Important

Nodetool and sstable commands are in public preview. This feature is provided without a service level agreement, and it's not recommended for production workloads. For more information, see Supplemental Terms of Use for Microsoft Azure Previews.

DBA command support

Azure Managed Instance for Apache Cassandra allows you to run nodetool and sstable commands via Azure CLI, for routine DBA administration. Not all commands are supported and there are some limitations. For supported commands, see the sections below.

Warning

Some of these commands can destabilize the cassandra cluster and should only be run carefully and after being tested in non-production environments. Where possible a --dry-run option should be deployed first. Microsoft cannot offer any SLA or support on issues with running commands which alter the default database configuration and/or tables.

How to run a nodetool command

Azure Managed Instance for Apache Cassandra provides the following Azure CLI command to run DBA commands:

    az managed-cassandra cluster invoke-command  --resource-group  <rg>   --cluster-name <cluster> --host <ip of data node> --command-name nodetool --arguments "<nodetool-subcommand>"="" "paramerter1"=""

The particular subcommand needs to be in the --arguments section with an empty value. Nodetool flags without a value are in the form: "<flag>"="". If the flag has a value, it is in the form: "<flag>"="value".

Here's an example of how to run a nodetool command without flags, in this case the nodetool status command:

    az managed-cassandra cluster invoke-command  --resource-group  <rg>   --cluster-name <cluster> --host <ip of data node> --command-name nodetool --arguments "status"=""

Here's an example of how to run a nodetool command with a flag, in this case the nodetool compact command:

    az managed-cassandra cluster invoke-command  --resource-group  <rg>   --cluster-name <cluster> --host <ip of data node> --command-name nodetool --arguments "compact"="" "-st"="65678794"

Both will return a json of the following form:

    {
        "commandErrorOutput": "",
        "commandOutput": "<result>",
        "exitCode": 0
    }

In most cases you might only need the commandOutput or the exitCode. Here is an example for only getting the commandOutput:

    az managed-cassandra cluster invoke-command --query "commandOutput" --resource-group $resourceGroupName --cluster-name $clusterName --host $host --command-name nodetool --arguments getstreamthroughput=""

How to run an sstable command

The sstable commands require read/write access to the Cassandra data directory and the Cassandra database to be stopped. To accommodate this, two extra parameters --cassandra-stop-start true and --readwrite true need to be given:

    az managed-cassandra cluster invoke-command  --resource-group  <test-rg>   --cluster-name <test-cluster> --host <ip> --cassandra-stop-start true --readwrite true  --command-name sstableutil --arguments "system"="peers"

    {
    "commandErrorOutput": "",
    "commandOutput": "Listing files...\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-CompressionInfo.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Data.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Digest.crc32\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Filter.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Index.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Statistics.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-Summary.db\n/var/lib/cassandra/data/system/peers-37f71aca7dc2383ba70672528af04d4f/me-1-big-TOC.txt\n",
    "exitCode": 0
    }

How to run other commands

The cassandra-reset-password command lets a user change their password for the Cassandra user.

    az managed-cassandra cluster invoke-command --resource-group <rg> --cluster-name <cluster> --host <ip of data node> --command-name cassandra-reset-password --arguments password="<password>"

Important

The password is URL encoded (UTF-8) when it is passed into this command, meaning the following rules apply:

  • The alphanumeric characters "a" through "z", "A" through "Z" and "0" through "9" remain the same.
  • The special characters ".", "-", "*", and "_" remain the same.
  • The space character " " is converted into a plus sign "+".
  • All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string "%xy", where xy is the two-digit hexadecimal representation of the byte.

The cassandra-reset-auth-replication command lets a user change their schema for the Cassandra user. Separate the datacenter names by space.

    az managed-cassandra cluster invoke-command --resource-group <rg> --cluster-name <cluster> --host <ip of data node> --command-name cassandra-reset-auth-replication --arguments password="<datacenters>"

Important

The datacenters are URL encoded (UTF-8) when they are passed into this command, meaning the following rules apply:

  • The alphanumeric characters "a" through "z", "A" through "Z" and "0" through "9" remain the same.
  • The special characters ".", "-", "*", and "_" remain the same.
  • The space character " " is converted into a plus sign "+".
  • All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string "%xy", where xy is the two-digit hexadecimal representation of the byte.

The sstable-tree command lets a user see their sstables.

    az managed-cassandra cluster invoke-command --resource-group <rg> --cluster-name <cluster> --host <ip of data node> --command-name sstable-tree

The sstable-delete command lets a user delete their sstables made before a certain time.

    az managed-cassandra cluster invoke-command --resource-group <rg> --cluster-name <cluster> --host <ip of data node> --command-name sstable-delete --arguments datetime="<YYYY-MM-DD hh:mm:ss>"

Datetime argument must be formatted as shown above. You can also add --dry-run="" as an argument to see which files will be deleted.

List of supported sstable commands

For more information on each command, see https://cassandra.apache.org/doc/latest/cassandra/tools/sstable/index.html

  • sstableverify
  • sstablescrub
  • sstablemetadata
  • sstablelevelreset
  • sstableutil
  • sstablesplit
  • sstablerepairedset
  • sstableofflinerelevel
  • sstableexpiredblockers

List of supported nodetool commands

For more information on each command, see https://cassandra.apache.org/doc/latest/cassandra/tools/nodetool/nodetool.html

  • status
  • cleanup
  • clearsnapshot
  • compact
  • compactionhistory
  • compactionstats
  • describecluster
  • describering
  • disableautocompaction
  • disablehandoff
  • disablehintsfordc
  • drain
  • enableautocompaction
  • enablehandoff
  • enablehintsfordc
  • failuredetector
  • flush
  • garbagecollect
  • gcstats
  • getcompactionthreshold
  • getcompactionthroughput
  • getconcurrentcompactors
  • getendpoints
  • getinterdcstreamthroughput
  • getlogginglevels
  • getsstables
  • getstreamthroughput
  • gettimeout
  • gettraceprobability
  • gossipinfo
  • info
  • invalidatecountercache
  • invalidatekeycache
  • invalidaterowcache
  • listsnapshots
  • netstats
  • pausehandoff
  • proxyhistograms
  • rangekeysample
  • rebuild
  • rebuild_index - for arguments use "keyspace"="table indexname..."
  • refresh
  • refreshsizeestimates
  • reloadlocalschema
  • replaybatchlog
  • resetlocalschema
  • resumehandoff
  • ring
  • scrub
  • setcachecapacity - for arguments use "key-cache-capacity" = "<row-cache-capacity> <counter-cache-capacity>"
  • setcachekeystosave - for arguments use "key-cache-keys-to-save":"<row-cache-keys-to-save> <counter-cache-keys-to-save>"
  • setcompactionthreshold - for arguments use "<keyspace>"="<table> <minthreshold> <maxthreshold>
  • setcompactionthroughput
  • setconcurrentcompactors
  • sethintedhandoffthrottlekb
  • setinterdcstreamthroughput
  • setstreamthroughput
  • settimeout
  • settraceprobability
  • statusbackup
  • statusbinary
  • statusgossip
  • statushandoff
  • stop
  • tablehistograms
  • tablestats
  • toppartitions
  • tpstats
  • truncatehints
  • verify
  • version
  • viewbuildstatus

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