Exploring SVN / GIT and Jenkins integration

Was working on creating a test SVN repository for testing purposes.
I have worked extensively with CVS before in my experience in HP enterprise services, but done limited work with SVN.

SVN is much better CM tool and offers a set of decent web interfaces and integrates well with apache.
Jenkins also supports GIT, which would be my next logical step.
Jenkins can do a lot integrating with a CM tool from doing old style deployment to distributing codes and scripts to different parts of a given system.
Jenkins has the ability to managed remote nodes and can even work with standard password authentication. handles all the overhead beautifully :)

Setting up GIT is similar to SVN.
Now following the below link to setup a GIT repository for testing.
http://git-scm.com/book/en/Git-on-the-Server-Setting-Up-the-Server

integrating git with Jenkins would work straight forward similar to SVN.

 

TC server JMX trap !

From: http://static.springsource.com/projects/tc-server/2.0/admin/htmlsingle/admin.html#manual



Warning: The value of the bind attribute of JmxSocketListener overrides the value of the java.rmi.server.hostname Java system property. This directly affects how names are bound in the RMI registries; by default, the names will be bound to localhost (127.0.0.1.) This in turn means that RMI clients running on a different host from the one hosting the tc Runtime instance will be unable to access the RMI objects because, from their perspective, the host name is incorrect. This is because, the host should be the name or IP address of the tc Runtime computer rather than localhost. When the tc Runtime instance starts, if it finds that the value of the bind attribute is different from or incompatible with the java.rmi.server.hostname Java system property, the instance will log a warning but will startup anyway and override the system property as described. If this causes problems in your particular environment, then you should change the value of the bind attribute to specify the actual hostname on which the tc Runtime runs rather than the default 127.0.0.1 value.


The above has cause me to work for 4 hours looping in circles !!!
Tomcat just rocks !!

JMX on TC Server (Tomcat)

Currently working on a PoC to enable remote JMX on TC server.

The config to do this goes into 3 places:
1- Setenv.sh:
needs to put in JVM parameters to allow JMX remotely using authentication

JMX_OPTS="-Dcom.sun.management.jmxremote
  -Dcom.sun.management.jmxremote.port=16001
  -Dcom.sun.management.jmxremote.ssl=false
  -Dcom.sun.management.jmxremote.authenticate=true
  -Dcom.sun.management.jmxremote.password.file=${CATALINA_BASE}/conf/jmxremote.password
  -Dcom.sun.management.jmxremote.access.file=${CATALINA_BASE}/conf/jmxremote.access"

2- jmxremote.access:
[root@khofo05 conf]# cat jmxremote.access
#admin readonly
admin readwrite
[root@khofo05 conf]#

3- jmxremote.password
[root@khofo05 conf]# cat jmxremote.password
# The "admin" role has password "springsource".
admin springsource
[root@khofo05 conf]#

The above is sufficient to have an authenticated remote JMX up and running on any tomcat.

I wanted to explore using SSL, for more protection since JMX would allow altering server parameters if readwrite rule is required, but since I need JMX  for monitoring purpose is would just need to have read only rules.

After some reading and consulting my colleges i decided to abandon JMX and go with Jstatd instead.

AWK string manipulations

The below script is used to scan a full text file line by line for a certain pattern.
Once this pattern is found,
The script does another pattern matching to do another change in that same line.

[root@khofo05 sherif]$  awk -v FILENAME=./server.xml_20131127_1 -f ./change_ds.awk >server.xml
[root@khofo05 sherif]$ cat change_ds.awk
BEGIN{
        i=0;
        line="";
        while (getline line < FILENAME)
        {
                gotit=match(line,"DB1");
                if (gotit == 0)
                {
                        print(line);
                }
                else if (gotit > 0 )
                {
                        #print ("match------",line);
                        newsvr=gsub("db111oracle.example.com","db123oracle.example.com",line);
                        newsid=gsub("DB1","DB3",line);
                        #print (newsvr,newsid,line);
                        print (line);
                        #break;
                }
        }
}
[root@khofo05 sherif]$


The above is an example for a mass change in a server.xml file for changing a Datasource definition from a SID/host to another SID/host.
Would be useful if multiple datasources are involved.

Extracting a part of the JVM startup command

This  One is used to extract the Catalina base directory from a running TC server process.
This is useful for monitoring what applications are being deployed on those TC instances.

 
[root@khofo05 ~]# ps -ef |grep java|grep 18001
root     20342     1  0 Jan20 ?        00:01:05 /apps/admngop1/springsource/jdk1.6/bin/java -Djava.util.logging.config.file=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001/conf/logging.properties -Xmx512M -Xss192K -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=16001 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.password.file=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001/conf/jmxremote.password -Dcom.sun.management.jmxremote.access.file=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001/conf/jmxremote.access -Djava.util.logging.manager=com.springsource.tcserver.serviceability.logging.TcServerLogManager -Djava.endorsed.dirs=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/tomcat-6.0.35.A.RELEASE/endorsed -classpath /apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/tomcat-6.0.35.A.RELEASE/bin/bootstrap.jar -Dcatalina.base=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001 -Dcatalina.home=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/tomcat-6.0.35.A.RELEASE -Djava.io.tmpdir=/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001/temp org.apache.catalina.startup.Bootstrap start


[root@khofo05 ~]# JAVA_CMD=`ps -ef |grep java|grep 18001`
[root@khofo05 ~]# CATALINA_BASE=`echo ${JAVA_CMD##*Dcatalina.base}|cut -d "=" -f2|cut -d" " -f1`

[root@khofo05 ~]# echo $CATALINA_BASE
/apps/admngop1/springsource/vfabric-tc-server-standard-2.6.3.RELEASE/khofo05_18001
[root@khofo05 ~]#

This would allow to check the webapps folder, the conf and others.
Thought to document the bash string concat constructs, never used it before :)

Running a Shell script from an HTML page using NodeJs as backend

The below code is a modified version from the one used for PHP on this link: http://www.scriptol.com/javascript/nodejs-php.php

This functionality could be useful in doing many automation tasks for Ops, though could be done by other tools like Puppet or even Jenkins but NodeJs is very light weight and quite fast.
Would plan to integrate this in my HTML status pages in the future.

The code:

var sys = require("sys"), 
http = require("http"),   
path = require("path"),
url = require("url"),
filesys = require("fs"),
runner = require("child_process");

function sendError(errCode, errString, response)
{
  response.writeHead(errCode, {"Content-Type": "text/plain;charset=utf-8"});
  response.write(errString + "\n");
  response.end();
  return false;
}

function sendData(err, stdout, stderr, response)
{
  if (err) return sendError(500, stderr, response);
  response.writeHead(200,{"Content-Type": "text/plain;charset=utf-8"});
  response.write(stdout);
  response.end();
}

function runScript(exists, file, response)
{
  if(!exists) return sendError(404, 'File not found', response);
  runner.exec(file ,
   function(err, stdout, stderr) { sendData(err, stdout, stderr, response); });
}

function myshell(request, response)
{
  var urlpath = url.parse(request.url).pathname;
  //var param = url.parse(request.url).query;
  var localpath = path.join("/", urlpath);
  console.log(localpath);
  filesys.exists(localpath, function(result) { runScript(result, localpath, response)});
}

var server = http.createServer(myshell);
server.listen(7071);
console.log("Shell ready to run script given on port 7071.");


HTML:

<html>

<head>
<meta http-equiv="refresh" content="600" />
</head>
               <body>
                <br>
                <a href=http://localhost:7071/bin/ls>Run ls Locally</a>
                <br>
                <br>
        </body>
</html>

Jstatd configuration for JVM monitoring

Currently I am busy setting up configuration for running Jstatd on a multiple set of VMs runing Spring source TC servers.
The setup is simple, use a script to start the jstatd locally and invoke the script from a master VM to start on all nodes.
Jstatd is useful for memory monitoring for performance testing of Java applications and can provide realtime info about the JVM execution.

In our case Jstatd is much better than using traditional JMX parameters on JVM, JMX would need to be secured and have a strong authentication and authorization in place to secure the application.
This can be done, but the amount of config changes wouldn't be easily done unless we have a Dev-Ops tool like puppet to handle.

Jstatd is zero config from application point of view, just put the policy file and start the deamon and ur done !!

To start Jstatd on a server you need a policy file: jstatd.all.policy
 That contains:
grant codebase "file:${java.home}/../lib/tools.jar" { permission java.security.AllPermission; };

and just run as:

JAVA_HOME/bin/jstatd -J-Djava.security.policy=jstatd.all.policy

Jstatd uses port 1099 (RMI) to expose JVM info like memory and thread usage.
Jstatd also exposes all JVMs running on the same server using one jstatd process.

We can use jvisualvm tool provided by Java SDK to connect to remote Jstatd and browse the needed info.