HAProxy

HAProxy                                                                                                                    

Introduction:

HAProxy, which stands for High Availability Proxy. Its most common use is to improve the performance and reliability of a server environment by distributing the workload across multiple servers.

HAProxy is a popular open source software TCP/HTTP Load Balancer and proxying solution which can be run on Linux, Solaris, and FreeBSD.

It is used in many high-profile environments, including: GitHub, Imgur, etc...

                                                                       HAProxy Diagram

Frontend:
A frontend defines how requests should be forwarded to backends. Frontends are defined in the frontend section of the HAProxy configuration. Their definitions are composed of the following components.

A set of IP addresses and Port no.

o    Ex: 192.xx.xx.xx,*:443.

Backend:

A backend is a set of servers that receives forwarded requests. Backends are defined in the backend section of the HAProxy configuration. In this most basic form, a backend can be defined by: 

• A list of servers and Ports.
•  Which load balance algorithm to use.

A backend can contain one or more servers in it. Adding more servers to your Backend will increase potential load capacity by spreading the load over multiple servers.

Increase reliability is also achieved through this method, if some of backend servers become unavailable.

Load Balancing Algorithms:

The load balancing algorithm that is used to determines which server, in Backend, will be selected when load balancing.

Roundrobin: Roundrobin selects servers in turns. This is the Default algorithm.

Leastconn: Selects the Server with the least number of connections. It is recommended for longer sessions.

HAProxy Installation:

• # sudo apt-get install -y haproxy

                      (or)

• # sudo yum install -y haproxy

HAProxy configuration

HAProxy configuration can be found at /etc/haproxy/haproxy.cfg

global

    daemon

    maxconn 256

defaults

    mode http

    timeout connect 5000ms

    timeout client 50000ms

    timeout server 50000ms

frontend http-in

    bind *:80

    balance roundrobin

    default_backend servers

backends servers

     server1 192.xx.xx.xx:8080 check maxconn 32

      server2 192.xx.xx.xx:8080 check maxconn 32

Enable HAProxy

• We need to enable HAProxy to be started by the init script

            /etc/default/haproxy.

• Set ENABLED option to 1 as:

                                           ENABLED=1

To Start HAProxy service:

• # service haproxy restart

Testing Load-Balancing and Fail-over

•   Start the service backend servers
•   Then test in HAProxy Servers

                     # while true;do curl http://localhost; sleep 1; done

• Open HAProxy IP in Browser and check load-balancing and fail-over

WebLogic Default Admin User's Password change/Reset

   

Situation: Change/Reset the WebLogic Default Admin User's Password

Solution:  we have two methods to change the WebLogic Default Admin User's Password        

•            If you know the Admin password
•         If you don’t know the Admin Password, we need to reset the Password.

è If you Know the Admin Password

Ø  Login into Weblogic console.

http://hostname:port/console

Take "Lock & Edit"

Home -->Summary of Security Realms -->myrealm >User and Groups -->Users

Click on "Customize this table."

Filter by Column: Name --> Enter WebLogic Admin UserName as part of "Criteria."

Click "Apply."

Ø  Changed WebLogic Admin User Password:

Click on "WebLogic Admin UserName" --> Go to Passwords Tab.

Enter a new password for:

*New Password:

*Confirm New Password:

Click on "Save."

Ø  ShutDown Managed Servers:

Login into WebLogic console.

http://hostname:port /console

Take "Lock & Edit"

Environment --> servers --> Control --> Check All managed server --> Shutdown-->Force Shutdown now.

Ø  Shutdown Weblogic Admin server

            Take "Lock & Edit"

Environment --> servers --> Control --> AdminServer --> Shutdown-->Force Shutdown now.

Ø  Change Boot.properties

# $DOMAIN_HOME/servers/$ADMINSERVER_NAME/security

# cp -p boot.properties boot.properties_bkp

# vi boot.properties

username=” weblogic username”

password=” New Password”

Ø  Clear Tmp and cache folders for WebLogic Servers

# $DOMAIN_HOME/servers/SERVER_NAME

# rm -R tmp cache

Ø  Start Weblogic Admin server

# $DOMAIN_HOME/bin

# nohup ./startWebLogic.sh &

Ø  Start Weblogic Managed Servers

Login into Weblogic console.

http://hostname:port /console

Take "Lock & Edit"

Environment --> servers --> Control --> Check All managed server --> Start.

è If you Don’t Know Admin password, Reset Admin Password

    Ø  ShutDown Managed Servers:

Login into Weblogic console.

http://hostname:port /console

Take "Lock & Edit"

Environment --> servers --> Control --> Check All managed server --> Shutdown-->Force ShutDown now.

    Ø  Shutdown Weblogic Admin server

Environment --> servers --> Control --> AdminServer --> Shutdown-->Force ShutDown now.

  Ø  Move of LDAP folder for Adminserver and Manager server.

# $DOMAIN_HOME/servers/SERVER_NAME/data/ldap

# mv ldap ldap_bkp

*Note: If we move ldap folder, We may lose the privileges for user Global roles.

Ø  Set the Environment Variable

# $DOMAIN_HOME/bin

# . ./setDomainEnv.sh

Ø  Backup  DefaultAuthenticatormyrealmInit.initialized file from ldap folder.

# $ DOMAIN_HOME/servers/AdminServer/data/ldap

#  mv DefaultAuthenticatormyrealmInit.initialized DefaultAuthenticatormyrealmInit.initialized_bkp

Ø  Create a new initialization

                   Create a new initialization file for the default authenticator by running the                                             below command that creates a new DefaultAuthenticatorInit.ldift file in the                                          $DOMAIN_HOME/security subdirectory

                   #java weblogic.security.utils.AdminAccount <username > <newpassword>                                           $DOMAIN_HOME/security

 Ø  Create a boot. Properties file with new username and password already used on the previous step.

# $DOMAIN_HOME/servers/AdminServer/security

# cp -p boot.properties boot.properties_bkp

# vi boot.properties

username=” weblogic username”

password=” New Password”

Ø  Start Weblogic Admin server

# $DOMAIN_HOME/bin

# nohup ./startWebLogic.sh &

Once the admin server comes up and running Weblogic Server will encrypt the password in boot.properties file.

Ø  Start Weblogic Managed Servers

Login into Weblogic console.

http://hostname:port /console

Take "Lock & Edit"

Environment --> servers --> Control --> Check All managed server --> Start.