MarkLogic 9 Product Documentation

Scripting Administrative Tasks Guide — Chapter 8

Coupling the Master and Replica Clusters

Use GET /manage/v2/properties to return the properties of each cluster to participate in the database replication configuration and pass the properties to POST /manage/v2/clusters to couple the clusters.

The example Python script below gets the properties (in JSON format) from the master and replica clusters and passes the master properties to the replica cluster and the replica properties to the master cluster.

#! /usr/bin/env python
# -*- coding: utf-8 -*-

import json
import requests
from requests.auth import HTTPDigestAuth
from pprint import pprint

def main():

       # Get the properties for each cluster to be coupled

       auth = HTTPDigestAuth('admin', 'admin')
       headers = {'accept': 'application/json'}
       masterURI = 'http://master.marklogic.com:8002/manage/v2/properties'
       replicaURI = 'http://replica.marklogic.com:8002/manage/v2/properties'

       g1 = requests.get(masterURI, auth=auth, headers=headers)
       master_info = g1.json()

       g2 = requests.get(replicaURI, auth=auth, headers=headers)
       replica_info = g2.json()

       # Couple the clusters

       masterURI = 'http://master.marklogic.com:8002/manage/v2/clusters'
       replicaURI = 'http://replica.marklogic.com:8002/manage/v2/clusters'	
       headers = {'content-type': 'application/json'}

       p1 = requests.post(masterURI, auth=auth,
                          data=json.dumps(replica_info), 
                          headers=headers)

       p2 = requests.post(replicaURI, auth=auth,
                          data=json.dumps(master_info), 
                          headers=headers)	

       # Return reponses from the REST calls

       print p1.text 
       print p2.text 

main()

POST /manage/v2/clusters accepts all of the properties returned from GET /manage/v2/properties as its payload. Should you have a need for finer control over the cluster properties when coupling clusters, you can manually build the payload for POST /manage/v2/clusters.

The Python script below extracts the properties from the master cluster and builds the payload needed by POST /manage/v2/clusters to couple the replica cluster to the master cluster. You would need to write similar code to couple the master cluster to the replica cluster.

#! /usr/bin/env python
# -*- coding: utf-8 -*-

import json
import requests
from requests.auth import HTTPDigestAuth
from pprint import pprint

def main():

       # Get the properties for master cluster

       auth = HTTPDigestAuth('admin', 'admin')
       headers = {'accept': 'application/json'}
       masterURI = 'http://master.marklogic.com:8002/manage/v2/properties'

       g1 = requests.get(masterURI, auth=auth, headers=headers)
       master_info = g1.json()

       # Extract the properties needed by POST:/manage/v2/clusters
       fhostid = master_info['bootstrap-host'][0]['bootstrap-host-id']
       fhostn = master_info['bootstrap-host'][0]['bootstrap-host-name']
       fcid = master_info['cluster-id']
       fcn = master_info['cluster-name']
       fccert = master_info['xdqp-ssl-certificate']

       # Build the payload for POST:/manage/v2/clusters
       payload = {
         "foreign-cluster-id": fcid,
         "foreign-cluster-name": fcn,
         "foreign-protocol": "http",
         "foreign-ssl-certificate": fccert,
         "xdqp-ssl-enabled": True,
         "xdqp-ssl-allow-sslv3": True,
         "xdqp-ssl-allow-tls": True,
         "xdqp-ssl-ciphers": "ALL:!LOW:@STRENGTH",
         "xdqp-timeout": 10,
         "host-timeout": 30,
         "foreign-bootstrap-host": [{
         "foreign-host-id": fhostid,
         "foreign-host-name": fhostn,
         "foreign-connect-port": 7998
         }]}

       # Couple the replica cluster to the master cluster. 

         url = 'http://replica.marklogic.com:8002/manage/v2/clusters'
         headers = {'content-type': 'application/json'}

         r = requests.post(url, auth=auth, data=json.dumps(payload),
                           headers=headers)

       # Return reponse from the REST call

         print r.text

main()

Setting the Master and Replica Databases

Once the clusters are coupled you can use POST /manage/v2/databases/{id|name} to configure the master and replica databases.

The Python script below uses POST /manage/v2/databases/{id|name} to configure the Documents database on the master cluster as the master database and the Documents database on the replica cluster as the replica database.

#! /usr/bin/env python
# -*- coding: utf-8 -*-

import json
import requests
from requests.auth import HTTPDigestAuth
from pprint import pprint

def main():

       # Define the operations to set the master and replica databases. 

        set_master = {
          "operation": "set-foreign-master",
          "foreign-master": {
             "foreign-cluster-name": "master.marklogic.com-cluster",
             "foreign-database-name": "Documents",
             "connect-forests-by-name": True}} 

        set_replica = {
          "operation": "add-foreign-replicas",
          "foreign-replica": [{
             "foreign-cluster-name": "replica.marklogic.com-cluster",
             "foreign-database-name": "Documents",
             "connect-forests-by-name": True,
             "lag-limit": 23,
             "enabled": True}]}

        masterURI =
          'http://master.marklogic.com:8002/manage/v2/databases/Documents'

        replicaURI =
          'http://replica.marklogic.com:8002/manage/v2/databases/Documents'	

        headers = {'content-type': 'application/json', 
                   'accept': 'application/json'}

       # Set the master and replica databases.

        r1 = requests.post(replicaURI, auth=HTTPDigestAuth('admin', 'admin'),
                           data=json.dumps(set_master), headers=headers)	

        r2 = requests.post(masterURI, auth=HTTPDigestAuth('admin', 'admin'),
                           data=json.dumps(set_replica), headers=headers)

       # Return reponses from the REST calls

        print r1.text
        print r2.text

main()