Premium HA - Rebuild data center

Premium High Availability

Dynatrace Premium High Availability (Premium HA) is a self-contained, out-of-the-box solution that provides near-zero downtime and allows monitoring to continue without data loss in failover scenarios. This solution requires additional licensing for your deployment.

In this recovery procedure, the following terms are designated as follows:

  • Source-DC - Source (surviving) data center where the Managed cluster is located.
  • Target-DC - Target (lost) data center designated for recovery.
  • seed node - Any node within Source-DC that will be used for performing the installation tasks and distribution of configuration.

The procedure involves migration and replication of Dynatrace Managed components separately so they are prepared for data replication across two data centers. See Overview of Dynatrace Managed components.

Step 1

Terminate unavailable data center

Step 2

Remove nodes

Step 3

Remove lost data center from configuration

Step 4

Distribute the installer

Step 5

Prepare cluster data for a replication

Step 6

Create the data center topology

Step 7

Open firewall rules

Step 8

Install second data center nodes

Step 9

Migrate Cassandra

Step 10

Migrate Elasticsearch

Step 11

Migrate the server

Step 12

Enable the restored data center

Gather information

The commands will use these variables in executing the REST API calls. For this, you will need the following information:

  • <seed-node-ip> - The IP address of the seed node from Source-DC.
    This can be any node running in existing data center that will be used for performing the installation tasks and distribution of configuration.

  • <nodes-ips> - The list of IPV4 addresses of new nodes in Target-DC.
    Example: "176.16.0.5", "176.16.0.6", "176.16.0.7"

  • <api-token> - A valid Cluster API token (ServiceProviderAPI scope is required).
    You can generate it in the Managed Cluster Management Console. See Cluster API - Authentication.

  • <dynatrace-directory> - The directory where Dynatrace Managed is installed on the seed node.
    The default Dynatrace Managed installation directory is /opt/dynatrace-managed

  • <datacenter-1> - The Source-DC name must be the same as the Cassandra DC name.
    The default Cassandra DC name is datacenter1.

    To get the DC name, execute this command on the seed node before starting migration:

    sudo <dynatrace-directory>/utils/cassandra-nodetool.sh status

    You will get a response that includes the Source-DC name. Example for a DC named datacenter1:

    Datacenter: datacenter1
    =======================
    Status=Up/Down
    |/ State=Normal/Leaving/Joining/Moving
    --  Address        Load       Tokens       Owns (effective)  Host ID                               Rack
    UN  10.176.42.20   65.54 GB   256          100.0%            f053dd8d-ecf3-7834-b099-68542439817b  rack1
    UN  10.176.42.244  65.47 GB   256          100.0%            2aa7e790-a423-9273-88f9-45bcd158dd6e  rack1
    UN  10.176.42.168  65.47 GB   256          100.0%            48543bca-41f5-26d3-b2fd-6cfdf5c0f3b2  rack1

  • <datacenter-2> - The Target-DC name must remain unchanged. Example: dc-us-east-2.

Lost data center name

You must use the same name of the lost data center during the recovery to Target-DC.

Set variables

Set the following environment variables on seed node in Source-DC and EACH NODE in Target-DC:

SEED_IP=<seed-ip>
DT_DIR=<dynatrace-directory>
NODES_IPS=echo '[<nodes-ips]'
API_TOKEN=<api-token>
SDC_NAME=<datacenter-1>
TDC_NAME=<datacenter-2>

For example:

SEED_IP=10.176.37.201
DT_DIR=/opt/dynatrace-managed
NODES_IPS=echo '["10.176.37.218", "10.176.37.227", "10.176.37.120"]'
API_TOKEN=R_SZOpV4RTOmjr9fFmK4x
SDC_NAME=datacenter1
TDC_NAME=dc-us-east-2

Check for custom settings

If your Cassandra or Elasticsearch cluster is configured with custom.settings that enable rack-awareness, contact a Dynatrace product expert via live chat to apply these custom settings before proceeding with Target-DC recovery.

To check whether custom settings are applied, execute on seed node:

ls $DT_DIR/installer/custom.settings

If the custom.settings file exists, you are using custom settings.

Recovery

To restore a cluster in a Target-DC, follow this procedure.

API return codes

Each of the REST API calls will return the HTTP code. Go to the next step only when the returned code is 200. Expect the following return codes:

200 - Go to the next step, current step was executed successfully.
207 - The request is being processed, repeat a step after few minutes.
40x - Revise your request path and arguments and repeat the request.
5xx - Contact support.

Step 1 Terminate unavailable data center

Stop all Dynatrace Managed required services in the recommended order. See Start/stop/restart a cluster.

Step 2 Remove nodes

  1. Go to the Dynatrace Managed Cluster Management Console.
  2. For each node in unavailable data center, go to the Node details page and remove the node.

For more information on other ways to remove a node, see Remove a cluster node.

Step 3 Remove lost data center from configuration

Execute the following cluster API call only on the seed node:

curl -ikS -X POST https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/lostDatacenterCleanUp?Api-Token=$API_TOKEN -H  "accept: application/json" -H  "Content-Type: application/json"

If the status code is not 200 and the response does not suggest next steps, contact a Dynatrace product expert via live chat.

Step 4 Distribute the installer

In this step, you will copy the node installer to every node in Target-DC.

  1. Log into your Dynatrace Managed Cluster Management Console.

  2. Go to Home for the Dynatrace Managed deployment status page.

  3. Click Add new cluster node.

  4. Copy the wget command line from the Run this command on the target host text box.

    Do not run the installer script

    The Run this installer script with root rights text box contains a command for the installation script. Ignore this command; do not execute the provided script.

  5. Paste and execute only the wget command line into your terminal window.

Step 5 Prepare cluster data for a replication

In this step, you will prepare data indexes for replication.

Prepare cluster data

Execute the following cluster API call only on the seed node:

curl -ikS -X POST https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/clusterReplicationPreparation?Api-Token=$API_TOKEN

If the status code is not 200 and the response does not suggest next steps, contact a Dynatrace product expert via live chat.

Check cluster preparation status

Execute the following cluster API call only on the seed node:

curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/clusterReplicationPreparation?Api-Token=$API_TOKEN -H  "accept: application/json"

If the status code from this call is not 200, try again after a few minutes.

Step 6 Create the data center topology

In this step, you will create configuration that maintains which nodes belong to which data center.

Execute the following cluster API call only on the seed node:

curl -ikS -X POST -d "{\"newDatacenterName\" : \"$TDC_NAME\", \"nodesIp\" :$NODES_IPS}" https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/datacenterTopology?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code is not 200 and the response does not suggest next steps, contact a Dynatrace product expert via live chat.

Step 7 Open firewall rules

In this step, you will add firewall rules that open ports to traffic from the Target-DC nodes.

Open ports

To open ports to traffic from the new Target-DC nodes, execute the following cluster API call only on the seed node:

curl -ikS -X POST -d "$NODES_IPS" https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/clusterNodes/currentDc?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If successful, status code will be 200 and the response body will contain a request ID you need to check the firewall rules status.

If the status code is not 200 and the response does not suggest next steps, contact a Dynatrace product expert via live chat.

Verify firewall rules

Set the request ID environment variable on seed node only. The request ID is from the response in the previous API call.

REQ_ID=<topology-configuration-request-id>

To check the firewall rules status, execute the following cluster API call only on the seed node:

curl -ikS https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/clusterNodes/currentDc/$REQ_ID?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code from this call is not 200, try again after a few minutes.

Step 8 Install second data center nodes

In this step, you will install managed nodes on all hosts within Target-DC and once completed, you will check for the presence of a Nodekeeper service. This will indicate if all nodes were successfully installed in Target-DC.

Install nodes in Target-DC

Execute the following command on every node in Target-DC. Follow the on-screen instructions as this will be a typical node installation.

sudo /bin/sh ./managed-installer.sh --install-new-dc --premium-ha on --datacenter $TDC_NAME --seed-auth $API_TOKEN

This operation should take about 3-5 minutes and the expected result should be similar to this:

Installation in new data center completed successfully after 2 minutes 51 seconds.

Check Nodekeeper in Target-DC

Execute the following cluster API call only on the seed node when all nodes in Target-DC finish installing:

curl -ikS https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/nodekeeper/healthCheck?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code is not 200, try again after a few minutes.

Step 9 Migrate Cassandra

In this step, you will reconfigure Cassandra in Source-DC and Target-DC for cross data center replication, trigger data synchronization, rebuild Cassandra data and verify Cassandra state.

It may take minutes to hours depending on your metric storage size.

  1. Migration of Cassandra in Target-DC

    In this step, you will reconfigure Cassandra for cross data center replication and trigger data synchronization.

    Migrate Cassandra

    To start migration of Cassandra in the Target-DC data center, execute the following cluster API call only on the seed node:

    curl -ikS -X POST https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/cassandra/newDc?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

    If successful, status code will be 200 and the response body will contain a request ID which you need to check migration status. Set the request ID environment variable only on the seed node. The request ID is from the response in the previous API call.

    REQ_ID=<migration-new-datacenter-request-id>

    If status code is not 200 and response does not suggest next steps, contact a Dynatrace product expert via live chat.

    Check migration status

    To check the migration status, execute the following cluster API call only on the seed node:

    curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/cassandra/newDc/$REQ_ID?Api-Token=$API_TOKEN -H  "accept: application/json" -H  "Content-Type: application/json"

    If the status code is not 200, try again after few minutes.

  2. Rebuild Cassandra data

    In this step, you'll rebuild Cassandra and verify the progress by checking the status. Depending on the size of your Cassandra database, this can take several hours.

    Rebuild data

    To rebuild Cassandra data in the Target-DC data center, execute the following cluster API call only on the seed node:

    curl -ikS -X POST https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/cassandra/rebuild?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

    If successful, the status code will be 200. If the status code is not 200 and the response does not suggest the following steps, please contact a Dynatrace ONE product specialist.

    Check the rebuild data status

    To check the rebuild data status, execute the following cluster API call only on the seed node:

    curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/cassandra/rebuild?Api-Token=$API_TOKEN -H  "accept: application/json" -H  "Content-Type: application/json"

    If the status code is not 200, try again after approximately 15 minutes. Remember that the rebuilding data process can be time-consuming.

    If the response has an error flag set to true, contact a Dynatrace product expert via live chat within your environment.

Step 10 Migrate Elasticsearch

In this step, you will migrate Elasticsearch to the Target-DC data center, verify the configuration and data migration. This step may take minutes or hours depending on your Elasticsearch storage.

Migrate Elasticsearch to Target-DC

Start Elasticsearch. Execute the following command successively on every node in Target-DC only:

sudo $DT_DIR/launcher/elasticsearch.sh start

To start migration of Elasticsearch to the Target-DC data center, execute the following cluster API call only on the seed node:

curl -ikS -X POST https://$SEED\_IP/api/v1.0/onpremise/multiDc/restore/elasticsearch/recover?Api-Token=$API\_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If successful, the status code will be 200.

Verify progress and status

To check the migration status of Elasticsearch, execute the following cluster API call only on the seed node:

curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/restore/elasticsearch/recover?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code is not 200, try again after a few minutes.

Verify data migration

To verify migration Elasticsearch data migration, execute the following cluster API call only on the seed node:

curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/migration/elasticsearch/indexMigrationStatus?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code is not 200, try again after a few minutes.

Step 11 Migrate the server

In this step, you will migrate the server, refresh authorization tokens that enable OneAgent connectivity, and start NGINX in the Target-DC data center. Also, you will refresh installers in Source-DC that are used to add nodes.

Migrate server

Launch the Managed cluster in the Target-DC by executing the following cluster API call only on the seed node:

curl -ikS -X POST https://$SEED_IP/api/v1.0/onpremise/multiDc/restore/server/recovery?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If successful, status code will be 200 and the response body will contain a request ID which you need to check cluster readiness. Set the request ID environment variable only on the seed node. The request ID is from the response in the previous API call.

REQ_ID=<migration-server-request-id>

If status code is not 200 and response does not suggest next steps, contact a Dynatrace product expert via live chat.

Check cluster readiness

To check if the cluster is ready, execute the following cluster API call only on the seed node:

curl -ikS -X GET https://$SEED_IP/api/v1.0/onpremise/multiDc/restore/server/recovery/$REQ_ID?Api-Token=$API_TOKEN -H "accept: application/json" -H "Content-Type: application/json"

If the status code is not 200, try again after a few minutes.

Step 12 Enable the restored data center

  1. Enable OneAgent traffic.
    For details, see Enable/Disable a cluster node.
  2. Enable backup in one of the data centers. Your backup is disabled after migration.
    For details, see Back up and restore a cluster.