VMware Tanzu GemFire in 15 Minutes or Less

Do you need a quick introduction to VMware Tanzu GemFire? Take this brief tour to try out basic features and functionality.

Step 1. Install Tanzu GemFire

See Installing Tanzu GemFire for instructions.

Step 2. Use gfsh to start a locator

In a terminal window, use the gfsh command line interface to start up a locator. gfsh (pronounced “jee-fish”) provides a single, intuitive command-line interface from which you can launch, manage, and monitor Tanzu GemFire processes, data, and applications. See gfsh.

The locator is a GemFire process that tells new, connecting members where running members are located and provides load balancing for server use. A locator, by default, starts up a JMX Manager, which is used for monitoring and managing a GemFire cluster. The cluster configuration service uses locators to persist and distribute cluster configurations to cluster members. See Running GemFire Locator Processes and Overview of the Cluster Configuration Service.

1. Create a scratch working directory (for example, my_gemfire) and change directories into it. gfsh saves locator and server working directories and log files in this location.

2. Start gfsh by typing gfsh at the command line (or gfsh.bat if you are using Windows).

       _________________________     __
      / _____/ ______/ ______/ /____/ /
     / /  __/ /___  /_____  / _____  /
    / /__/ / ____/  _____/ / /    / /
   /______/_/      /______/_/    /_/
   
   Monitor and Manage GemFire
   gfsh>
   

3. At the gfsh prompt, type the start locator command and specify a name for the locator:

   gfsh>start locator --name=locator1
   Starting a GemFire Locator in /home/username/my_gemfire/locator1...
   .................................
   Locator in /home/username/my_gemfire/locator1 on ubuntu.local[10334] as locator1 is currently online.
   Process ID: 3529
   Uptime: 18 seconds
   GemFire Version: 10.0.0
   Java Version: 11.0.17
   Log File: /home/username/my_gemfire/locator1/locator1.log
   JVM Arguments: -Dgemfire.enable-cluster-configuration=true -Dgemfire.load-cluster-configuration-from-dir=false
   -Dgemfire.launcher.registerSignalHandlers=true -Djava.awt.headless=true
   -Dsun.rmi.dgc.server.gcInterval=9223372036854775806
   Class-Path: /home/username/gf10/lib/gemfire-bootstrap-10.0.0.jar
   
   Successfully connected to: JMX Manager [host=ubuntu.local, port=1099]
   
   Cluster configuration service is up and running.
   

If you run start locator from gfsh without specifying the member name, gfsh will automatically pick a random member name. This is useful for automation.

Step 3. Start Pulse

Start up the browser-based Pulse monitoring tool. Pulse is a Web Application that provides a graphical dashboard for monitoring vital, real-time health and performance of GemFire clusters, members, and regions. See Tanzu GemFire Pulse.

gfsh>start pulse
Launched GemFire Pulse

This command launches Pulse and automatically connects you to the JMX Manager running in the Locator. At the Pulse login screen, type in the default username admin and password admin.

The Pulse application now displays the locator you just started (locator1):

Step 4. Start a server

A GemFire server is a Tanzu GemFire process that runs as a long-lived, configurable member of a cluster. The GemFire server is used primarily for hosting long-lived data regions and for running standard GemFire processes such as the server in a client/server configuration. See Running GemFire Server Processes.

Start the cache server:

gfsh>start server --name=server1 --server-port=40411

This commands starts a cache server named “server1” on the specified port of 40411.

If you run start server from gfsh without specifying the member name, gfsh will automatically pick a random member name. This is useful for automation.

Observe the changes (new member and server) in Pulse. Try expanding the distributed system icon to see the locator and cache server graphically.

Step 5. Create a replicated, persistent region

In this step you create a region with the gfsh command line utility. Regions are the core building blocks of the GemFire cluster and provide the means for organizing your data. The region you create for this exercise employs replication to replicate data across members of the cluster and utilizes persistence to save the data to disk. See Data Regions.

1. Create a replicated, persistent region:

   gfsh>create region --name=regionA --type=REPLICATE_PERSISTENT
   Member  | Status
   ------- | --------------------------------------
   server1 | Region "/regionA" created on "server1"
   

   Note that the region is hosted on server1.

2. Use the gfsh command line to view a list of the regions in the cluster.

   gfsh>list regions
   List of regions
   ---------------
   regionA
   

3. List the members of your cluster. The locator and cache server you started appear in the list:

   gfsh>list members
     Name       | Id
   ------------ | ---------------------------------------
   Coordinator: | 192.0.2.0(locator1:3529:locator)<ec><v0>:59926
   locator1     | 192.0.2.0(locator1:3529:locator)<v0>:59926
   server1      | 192.0.2.0(server1:3883)<v1>:65390
   

4. To view specifics about a region, type the following:

   gfsh>describe region --name=regionA
   ..........................................................
   Name            : regionA
   Data Policy     : persistent replicate
   Hosting Members : server1
   
   Non-Default Attributes Shared By Hosting Members
   
    Type  | Name | Value
   ------ | ---- | -----
   Region | size | 0
   

5. In Pulse, click the green cluster icon to see all the new members and new regions that you just added to your cluster.

Note: Keep this gfsh prompt open for the next steps.

Step 6. Manipulate data in the region and demonstrate persistence

Tanzu GemFire manages data as key/value pairs. In most applications, a Java program adds, deletes and modifies stored data. You can also use gfsh commands to add and retrieve data. See Data Commands

1. Run the following put commands to add some data to the region:

   gfsh>put --region=regionA --key="1" --value="one"
   Result      : true
   Key Class   : java.lang.String
   Key         : 1
   Value Class : java.lang.String
   Old Value   : <NULL>
   
   
   gfsh>put --region=regionA --key="2" --value="two"
   Result      : true
   Key Class   : java.lang.String
   Key         : 2
   Value Class : java.lang.String
   Old Value   : <NULL>
   

2. Run the following command to retrieve data from the region:

   gfsh>query --query="select * from /regionA"
   
   Result     : true
   startCount : 0
   endCount   : 20
   Rows       : 2
   
   Result
   ------
   two
   one
   

   Note that the result displays the values for the two data entries you created with the put commands.

   See Data Entries.

3. Stop the cache server using the following command:

   gfsh>stop server --name=server1
   Stopping Cache Server running in /home/username/my_gemfire/server1 on ubuntu.local[40411] as server1...
   Process ID: 3883
   Log File: /home/username/my_gemfire/server1/server1.log
   ....
   

4. Restart the cache server using the following command:

   gfsh>start server --name=server1 --server-port=40411
   

5. Run the following command to retrieve data from the region again – notice that the data is still available:

   gfsh>query --query="select * from /regionA"
   
   Result     : true
   startCount : 0
   endCount   : 20
   Rows       : 2
   
   Result
   ------
   two
   one
   

   Because regionA uses persistence, it writes a copy of the data to disk. When a server hosting regionA starts, the data is populated into the cache. Note that the result displays the values for the two data entries you created with the put commands prior to stopping the server.

   See Data Entries.

   See Data Regions.

Step 7. Examine the effects of replication

In this step, you start a second cache server. Because regionA is replicated, the data will be available on any server hosting the region.

1. Start a second cache server:

   gfsh>start server --name=server2 --server-port=40412
   

2. Run the describe region command to view information about regionA:

   gfsh>describe region --name=regionA
   ..........................................................
   Name            : regionA
   Data Policy     : persistent replicate
   Hosting Members : server1
                     server2
   
   Non-Default Attributes Shared By Hosting Members
   
    Type  | Name | Value
   ------ | ---- | -----
   Region | size | 2
   

   Note that you do not need to create regionA again for server2. The output of the command shows that regionA is hosted on both server1 and server2. When gfsh starts a server, it requests the configuration from the cluster configuration service which then distributes the shared configuration to any new servers joining the cluster.

3. Add a third data entry:

   gfsh>put --region=regionA --key="3" --value="three"
   Result      : true
   Key Class   : java.lang.String
   Key         : 3
   Value Class : java.lang.String
   Old Value   : <NULL>
   

4. Open the Pulse application (in a Web browser) and observe the cluster topology. You should see a locator with two attached servers. Click the Data tab to view information about regionA.

5. Stop the first cache server with the following command:

   gfsh>stop server --name=server1
   Stopping Cache Server running in /home/username/my_gemfire/server1 on ubuntu.local[40411] as server1...
   Process ID: 4064
   Log File: /home/username/my_gemfire/server1/server1.log
   ....
   

6. Retrieve data from the remaining cache server.

   gfsh>query --query="select * from /regionA"
   
   Result     : true
   startCount : 0
   endCount   : 20
   Rows       : 3
   
   Result
   ------
   two
   one
   three
   

   Note that the data contains 3 entries, including the entry you just added.

7. Add a fourth data entry:

   gfsh>put --region=regionA --key="4" --value="four"
   Result      : true
   Key Class   : java.lang.String
   Key         : 3
   Value Class : java.lang.String
   Old Value   : <NULL>
   

   Note that only server2 is running. Because the data is replicated and persisted, all of the data is still available. But the new data entry is currently available only on server 2.

   gfsh>describe region --name=regionA
   ..........................................................
   Name            : regionA
   Data Policy     : persistent replicate
   Hosting Members : server2
   
   Non-Default Attributes Shared By Hosting Members
   
    Type  | Name | Value
   ------ | ---- | -----
   Region | size | 4
   

8. Stop the remaining cache server:

   gfsh>stop server --name=server2
   Stopping Cache Server running in /home/username/my_gemfire/server2 on ubuntu.local[40412] as server2...
   Process ID: 4185
   Log File: /home/username/my_gemfire/server2/server2.log
   .....
   

Step 8. Restart the cache servers in parallel

In this step you restart the cache servers in parallel. Because the data is persisted, the data is available when the servers restart. Because the data is replicated, you must start the servers in parallel so that they can synchronize their data before starting.

1. Start server1. Because regionA is replicated and persistent, it needs data from the other server to start and waits for the server to start:

   gfsh>start server --name=server1 --server-port=40411
   Starting a GemFire Server in /home/username/my_gemfire/server1...
   

   Note that if you look in the server1.log file for the restarted server, you will see a log message similar to the following:

   [info 2015/01/14 09:08:13.610 PST server1 <main> tid=0x1] Region /regionA has pot
   entially stale data. It is waiting for another member to recover the latest data.
     My persistent id:
   
       DiskStore ID: 8e2d99a9-4725-47e6-800d-28a26e1d59b1
       Name: server1
       Location: /192.0.2.0:/home/username/my_gemfire/server1/.
   
     Members with potentially new data:
     [
       DiskStore ID: 2e91b003-8954-43f9-8ba9-3c5b0cdd4dfa
       Name: server2
       Location: /192.0.2.0:/home/username/my_gemfire/server2/.
     ]
     Use the gfsh "list-missing-disk-stores" command to see all disk stores that
   are being waited on by other members.
   

2. In a second terminal window, change directories to the scratch working directory (for example, my_gemfire) and start gfsh:

   [username@localhost ~/my_gemfire]$ gfsh
       _________________________     __
      / _____/ ______/ ______/ /____/ /
     / /  __/ /___  /_____  / _____  /
    / /__/ / ____/  _____/ / /    / /
   /______/_/      /______/_/    /_/
   
   Monitor and Manage GemFire
   

3. Run the following command to connect to the cluster:

   gfsh>connect --locator=localhost[10334]
   Connecting to Locator at [host=localhost, port=10334] ..
   Connecting to Manager at [host=ubuntu.local, port=1099] ..
   Successfully connected to: [host=ubuntu.local, port=1099]
   

4. Start server2:

   gfsh>start server --name=server2 --server-port=40412
   

   When server2 starts, note that server1 completes its start up in the first gfsh window:

   Server in /home/username/my_gemfire/server1 on ubuntu.local[40411] as server1 is currently online.
   Process ID: 3402
   Uptime: 1 minute 46 seconds
   GemFire Version: 10.0.0
   Java Version: 11.0.17
   Log File: /home/username/my_gemfire/server1/server1.log
   JVM Arguments: -Dgemfire.default.locators=192.0.2.0[10334] -Dgemfire.use-cluster-configuration=true
   -XX:OnOutOfMemoryError=kill -KILL %p -Dgemfire.launcher.registerSignalHandlers=true
   -Djava.awt.headless=true -Dsun.rmi.dgc.server.gcInterval=9223372036854775806
   Class-Path: /home/username/gf10/lib/gemfire-bootstrap-10.0.0.jar
   

5. Verify that the locator and two servers are running:

   gfsh>list members
     Name       | Id
   ------------ | ---------------------------------------
   Coordinator: | ubuntu(locator1:2813:locator)<ec><v0>:46644
   locator1     | ubuntu(locator1:2813:locator)<v0>:46644
   server2      | ubuntu(server2:3992)<v8>:21507
   server1      | ubuntu(server1:3402)<v7>:36532
   

6. Run a query to verify that all the data you entered with the put commands is available:

   gfsh>query --query="select * from /regionA"
   
   Result     : true
   startCount : 0
   endCount   : 20
   Rows       : 5
   
   Result
   ------
   one
   two
   four
   Three
   
   NEXT_STEP_NAME : END
   

7. Stop server2 with the following command:

   gfsh>stop server --dir=server2
   Stopping Cache Server running in /home/username/my_gemfire/server2 on 192.0.2.0[40412] as server2...
   Process ID: 3992
   Log File: /home/username/my_gemfire/server2/server2.log
   ....
   

8. Run a query to verify that all the data you entered with the put commands is still available:

   gfsh>query --query="select * from /regionA"
   
   Result     : true
   startCount : 0
   endCount   : 20
   Rows       : 5
   
   Result
   ------
   one
   two
   four
   Three
   
   NEXT_STEP_NAME : END
   

Step 9. Shut down the system including your locators

To shut down your cluster, do the following:

1. In the current gfsh session, stop the cluster:

   gfsh>shutdown --include-locators=true
   

   See shutdown.

2. When prompted, type ‘Y’ to confirm the shutdown of the cluster.

   As a lot of data in memory will be lost, including possibly events in queues,
   do you really want to shutdown the entire distributed system? (Y/n): Y
   Shutdown is triggered
   
   gfsh>
   No longer connected to ubuntu.local[1099].
   gfsh>
   

3. Type exit to quit the gfsh shell.

Step 10. What to do next…

Here are some suggestions on what to explore next with Tanzu GemFire:

• Continue reading the next section to learn more about the components and concepts that were just introduced.
• To get more practice using gfsh, see Tutorial—Performing Common Tasks with gfsh.
• To learn about the cluster configuration service, see Tutorial—Creating and Using a Cluster Configuration.