Using Logstash to Perform Incremental Data Migration

Logstash supports full data migration and incremental data migration. You can select full migration for the first time, and incremental migration for subsequent data migration. This section describes how to use Logstash to incrementally migrate cluster data. Incremental migration requires indexes with timestamps to identify incremental data.

Prepare for the migration by referring to Restrictions and Preparations. The procedure is as follows:

• Step 1: Creating a Logstash Cluster
• Step 2: Verifying Cluster Connectivity
• Step 3: Configuring a Logstash Incremental Data Migration Task
• Step 4: Performing an Incremental Data Migration
• Step 5: Deleting the Logstash Cluster

• Prepare the tools and software.

  The installation method is determined by whether the VM can be connected to the Internet. If VM can be connected to the Internet, use yum and pip to install the software. If VM cannot be connected to the Internet, download the installation package to the VM and run the installation commands.

  The online installation procedure is as follows:

  1. Run yum install python2 to install python2.

     [root@ecs opt]# yum install python2

  2. Run yum install python-pip to install pip.

     [root@ecs opt]# yum install python-pip

  3. Run pip install pyyaml to install the YAML dependency.
  4. Run pip install requests to install the requests dependency.

  The online installation procedure is as follows:

  1. Download the python2 installation package from https://www.python.org/downloads/release/python-2718/. Download and install the source code.
     Figure 1 Downloading the python2 package
     
  2. Use WinSCP to upload the Python installation package to the opt directory and install Python.

     # Decompress the Python package.
     [root@ecs-52bc opt]# tar -xvf Python-2.7.18.tgz
     Python-2.7.18/Modules/zlib/crc32.c
     Python-2.7.18/Modules/zlib/gzlib.c
     Python-2.7.18/Modules/zlib/inffast.c
     Python-2.7.18/Modules/zlib/example.c
     Python-2.7.18/Modules/python.c
     Python-2.7.18/Modules/nismodule.c
     Python-2.7.18/Modules/Setup.config.in
     ...
     # After the decompression, go to the directory.
     [root@ecs-52bc opt]# cd Python-2.7.18
     # Check the file configuration installation path.
     [root@ecs-52bc Python-2.7.18]# ./configure --prefix=/usr/local/python2
     ...
     checking for build directories... checking for --with-computed-gotos... no value specified
     checking whether gcc -pthread supports computed gotos... yes
     done
     checking for ensurepip... no
     configure: creating ./config.status
     config.status: creating Makefile.pre
     config.status: creating Modules/Setup.config
     config.status: creating Misc/python.pc
     config.status: creating Modules/ld_so_aix
     config.status: creating pyconfig.h
     creating Modules/Setup
     creating Modules/Setup.local
     creating Makefile
     # Compile Python.
     [root@ecs-52bc Python-2.7.18]# make
     # Install Python.
     [root@ecs-52bc Python-2.7.18]# make install

  3. Check the Python installation result.

     # Check the Python version.
     [root@ecs-52bc Python-2.7.18]# python --version
     Python 2.7.5
     # Check the pip version.
     [root@ecs-52bc Python-2.7.18]# pip --version
     pip 7.1.2 from /usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg (python 2.7)
     [root@ecs-52bc Python-2.7.18]#

• Prepare the execution script.
  1. Run the vi migrateConfig.yaml command to add configuration files.

     es_cluster_new:
     # Cluster name
       clustername: es_cluster_new
       # Address of the source Elasticsearch cluster, with http:// at the beginning
       src_ip: http://x.x.x.x:9200
       # If there is no username, set the password to "".
       src_username: ""
       src_password: ""
       # Address of the target Elasticsearch cluster, with http:// at the beginning
       dest_ip: http://x.x.x.x:9200
       # If there is no username, set the password to "".
       dest_username: ""
       dest_password: ""
       #This parameter is optional. The default value is false. It is used by migrateMapping.py.
       # Indicates whether to process only the mapping address indexes in the file.
       # If this parameter is set to true, only the indexes in the following mappings are obtained and created in the target.
       # If this parameter is set to false, all the indexes of the source cluster are obtained, excluding the following: .kibana, .*
       # Match the index names with the following mappings. If an index name matches a mapping, use the value of the mapping as the index name in the target.
       # If no match is found, the original index name in the source is used.
       only_mapping: false
       # Index to be migrated. key indicates the index name in the source, and value indicates the index name in the target.
       mapping:
           test_index_1: test_index_1
     
       # This parameter is optional. The default value is false. It is used by checkIndices.py.
       # If this parameter is set to false, all indexes and the number of documents are compared. If this parameter is set to true, only the number of indexes is compared.
       only_compare_index: false

     Configuration file parameters

     Configuration	Description
     clustername	Cluster name
     src_ip	IP address for accessing the source cluster. Only one IP address is required. The default port number is 9200. If the port number for accessing the cluster is not 9200, use the actual port number.
     src_username	Username for accessing the source cluster. If this parameter is not required, set it to "".
     src_password	Password for accessing the source cluster. If this parameter is not required, set it to "".
     dest_ip	IP address for accessing the target cluster. Only one IP address is required. The default port number is 9200. If the port number for accessing the cluster is not 9200, use the actual port number.
     dest_username	Username for accessing the target cluster. If this parameter is not required, set it to "".
     dest_password	Password for accessing the target cluster. If this parameter is not required, set it to "".

  2. Run the vi checkIndices.py command. Copy the following script to generate the index data comparison script:

     # -*- coding:UTF-8 -*-
     import sys
     import yaml
     import requests
     import re
     import json
     import os
     
     
     def printDividingLine():
         print("<=============================================================>")
     
     
     def get_cluster_version(url, auth=None):
         response = requests.get(url, auth=auth)
         if response.status_code != 200:
             print("*** get ElasticSearch message failed. resp statusCode:" + str(
                 response.status_code) + " response is " + response.text)
             return False
         cluster = response.json()
         version = cluster["version"]["number"]
         return True
     
     
     # get all indices
     def get_indices(url, source_auth):
         response = requests.get(url + "/_alias", auth=source_auth)
         if response.status_code != 200:
             print("*** get all index failed. resp statusCode:" + str(
                 response.status_code) + " response is " + response.text)
             exit()
         all_index = response.json()
         system_index = []
         create_index = []
         for index in list(all_index.keys()):
             if (index.startswith(".")):
                 system_index.append(index)
             else:
                 create_index.append(index)
         return create_index
     
     
     def get_mapping(url, _auth, index):
         source_url = url + "/" + index
         index_response = requests.get(source_url, auth=_auth)
         if index_response.status_code != 200:
             print("*** get ElasticSearch message failed. resp statusCode:" + str(
                 index_response.status_code) + " response is " + index_response.text)
             return "[failure] --- index is not exist in destination es. ---"
         mapping = index_response.json()
         return mapping
     
     
     def get_index_total(url, index, es_auth):
         stats_url = url + "/" + index + "/_stats"
         index_response = requests.get(stats_url, auth=es_auth, verify=False)
         if index_response.status_code != 200:
             print("*** get ElasticSearch stats message failed. resp statusCode:" + str(
                 index_response.status_code) + " response is " + index_response.text)
             return 0
         return index_response.json()
     
     
     def get_indices_stats(url, es_auth):
         endpoint = url + "/_cat/indices"
         indicesResult = requests.get(endpoint, es_auth)
         indicesList = indicesResult.split("\n")
         indexList = []
         for indices in indicesList:
             indexList.append(indices.split()[2])
         return indexList
     
     
     def loadConfig(argv):
         if argv is None or len(argv) != 2:
             config_yaml = "migrateConfig.yaml"
         else:
             config_yaml = argv[1]
         config_file = open(config_yaml)
         # python3
         # return yaml.load(config_file, Loader=yaml.FullLoader)
         return yaml.load(config_file)
     
     
     def main(argv):
         requests.packages.urllib3.disable_warnings()
         print("begin to migrate index mapping!")
         config = loadConfig(argv)
         src_clusters = config.keys()
     
         print("begin to process cluster name :")
         for name in src_clusters:
             print(name)
         print("cluster count:" + str(src_clusters.__len__()))
     
         for name, value in config.items():
             printDividingLine()
             source = value["src_ip"]
             source_user = value["src_username"]
             source_passwd = value["src_password"]
             source_auth = None
             if source_user != "":
                 source_auth = (source_user, source_passwd)
             dest = value["dest_ip"]
             dest_user = value["dest_username"]
             dest_passwd = value["dest_password"]
             dest_auth = None
             if dest_user != "":
                 dest_auth = (dest_user, dest_passwd)
             cluster_name = name
             if "clustername" in value:
                 cluster_name = value["clustername"]
     
             print("start to process cluster :" + cluster_name)
             # get all indices
             all_source_index = get_indices(source, source_auth)
             all_dest_index = get_indices(dest, dest_auth)
     
             if not os.path.exists("mappingLogs"):
                 os.makedirs("mappingLogs")
             filename = "mappingLogs/" + str(cluster_name) + "#indices_stats"
             with open(filename + ".json", "w") as f:
                 json.dump("cluster name: " + cluster_name, f)
                 f.write("\n")
                 json.dump("source indices: ", f)
                 f.write("\n")
                 json.dump(all_source_index, f, indent=4)
                 f.write("\n")
                 json.dump("destination indices : ", f)
                 f.write("\n")
                 json.dump(all_dest_index, f, indent=4)
                 f.write("\n")
     
             print("source indices total     : " + str(all_source_index.__len__()))
             print("destination index total  : " + str(all_dest_index.__len__()))
     
             filename_src = "mappingLogs/" + str(cluster_name) + "#indices_source_mapping"
             filename_dest = "mappingLogs/" + str(cluster_name) + "#indices_dest_mapping"
             with open(filename_src + ".json", "a") as f_src:
                 json.dump("cluster name: " + cluster_name, f_src)
                 f_src.write("\n")
             with open(filename_dest + ".json", "a") as f_dest:
                 json.dump("cluster name: " + cluster_name, f_dest)
                 f_dest.write("\n")
             for index in all_source_index:
                 mapping = get_mapping(source, source_auth, index)
                 with open(filename + ".json", "a") as f_src:
                     json.dump("========================", f_src)
                     f_src.write("\n")
                     json.dump(mapping, f_src, indent=4)
                     f_src.write("\n")
                 with open(filename_src + ".json", "a") as f_src:
                     json.dump("========================", f_src)
                     f_src.write("\n")
                     json.dump(mapping, f_src, indent=4)
                     f_src.write("\n")
     
                 mapping = get_mapping(dest, dest_auth, index)
                 with open(filename + ".json", "a") as f_dest:
                     json.dump("========================", f_dest)
                     f_dest.write("\n")
                     json.dump(mapping, f_dest, indent=4)
                     f_dest.write("\n")
                 with open(filename_dest + ".json", "a") as f_src:
                     json.dump("========================", f_src)
                     f_src.write("\n")
                     json.dump(mapping, f_src, indent=4)
                     f_src.write("\n")
     
             print("source indices write file success,      file: " + filename_src)
             print("destination indices write file success, file: " + filename_dest)
     
             if "only_compare_index" in value and value["only_compare_index"]:
                 print("[success] only compare mapping, not compare index count.")
                 continue
     
             for index in all_source_index:
                 index_total = get_index_total(value["src_ip"], index, source_auth)
                 src_total = index_total["_all"]["primaries"]["docs"]["count"]
                 src_size = int(index_total["_all"]["primaries"]["store"]["size_in_bytes"]) / 1024 / 1024
                 dest_index = get_index_total(value["dest_ip"], index, dest_auth)
                 if dest_index is 0:
                     print('[failure] not found, index: %-20s, source total: %-10s size %6sM'
                           % (str(index), str(src_total), src_size))
                     continue
                 dest_total = dest_index["_all"]["primaries"]["docs"]["count"]
                 if src_total != dest_total:
                     print('[failure] not consistent, '
                           'index: %-20s, source total: %-10s size %6sM destination total: %-10s '
                           % (str(index), str(src_total), src_size, str(dest_total)))
                     continue
                 print('[success] compare index total equal : index : %-20s,  total: %-20s '
                       % (str(index), str(dest_total)))
     
     
     if __name__ == '__main__':
         main(sys.argv)

Step 1: Creating a Logstash Cluster

• Logstash clusters are used to migrate data. By default, Logstash clusters are charged in pay-per-use mode. After data migration is complete, you are advised to delete the Logstash cluster to save costs.
• If there are multiple cluster indexes, you can create multiple Logstash clusters and configure different migration tasks for them.

1. Log in to the CSS management console.
2. On the Dashboard or Clusters page, choose Logstash in the navigation pane on the left.
3. Click Create Cluster. The Create Cluster page is displayed.
4. Specify Region and AZ.
5. Specify the basic cluster information, select the cluster type and cluster version, and enter the cluster name.

   Table 1 Basic parameters

   Parameter	Description
   Cluster Type	Select Logstash.
   Version	5.6.16 and 7.10.0 are supported. If the Elasticsearch cluster version is 5.x, select Logstash 5.6.16. If the Elasticsearch cluster version is 7.x, select Logstash 7.10.0.
   Name	Cluster name, which contains 4 to 32 characters. Only letters, numbers, hyphens (-), and underscores (_) are allowed and the value must start with a letter.

   Figure 2 Configuring basic information
   
6. Set host specifications of the cluster. Set the number of Nodes to 1. Set Node Specifications to 8 vCPUs | 16 GB and retain the default values for other parameters.
   Figure 3 Configuring host specifications
   
7. Set the enterprise project. Retain the default value.
8. Click Next: Configure Network. Configure the cluster network.

   Table 2 Parameter description

   Parameter	Description
   VPC	A VPC is a secure, isolated, and logical network environment. Select the target VPC. Click View VPC to enter the VPC management console and view the created VPC names and IDs. If no VPCs are available, create one. NOTE: The VPC must contain CIDRs. Otherwise, cluster creation will fail. By default, a VPC will contain CIDRs.
   Subnet	A subnet provides dedicated network resources that are isolated from other networks, improving network security. Select the target subnet. You can access the VPC management console to view the names and IDs of the existing subnets in the VPC.
   Security Group	A security group implements access control for ECSs that have the same security protection requirements in a VPC. To view more details about the security group, click View Security Group. NOTE: Ensure that Port Range/ICMP Type is Any or a port range includes port 9200 for the selected security group.

   Figure 4 Configuring network specifications
   
9. Click Next: Configure Advanced Settings. You can select Default or Custom for Advanced Settings. Retain the default settings in this example.
10. Click Next: Confirm. Check the configuration and click Next to create a cluster.
11. Click Back to Cluster List to switch to the Clusters page. The cluster you created is listed on the displayed page and its status is Creating. If the cluster is successfully created, its status will change to Available.