Tuesday, November 18, 2014

Some OS migration steps

Here are some basic system, application, database migration tasks.

System settings

1. Verify date format on old server and map the date format on new server.
2. Check the entry /etc/project (for solaris) file to see if there is any special values for Kernel.
3. Check kerboros settings (keytab, nfssec.conf, …etc)
4. Check mem/swap assigned to old server, allocate reasonable (or same ) size of swap space to new server.
5. Check the entry at /etc/syslog.conf to see if there are any app logs configured.
6. Check /etc/system and /etc/services for any configurations protocal including ports
7. Check /usr/, /usr/lib, /opt/, /usr/local for java, jre, or any other links and create links on new server. [ for db2 server/client]
8. Check crontab entries for root and inform user to copy their cron entry.
9. Keep the record of all the filessytem, process, ipaddress. (df -h, ps -ef, ifconfig)

Filesystem settings

1. Check all filesystem on the system. zfs does not have entry to vfstab so check one by one and create to target host.
   also check vfstab (fstab) entries for  app filesystems and NAS filesystems. Check to see if there any NAS filesystems that have kerberos enabled.
2. Copy any keys such as keytab, and apply to a new server.
3. Review and Copy all needed entries from /usr/local to new server.
4. Check autofs entry at /etc/auto_master, auto_home and auto_direct for automount filesystems. (linux/Solaris).
5. Make sure to put a ticket to storage team to allocate enough LUNs to copy data.
6. Start doing initial rsync between old server to new server.
7. Verify the autofs entry and if links are created, perform on target host aswell.
8. Check if there are any directories which are local to the system other then OS related. Copy if needed by creating new mountpoint. No local copy.
9. Also check /usr, /opt and /var filesystems, to see if there are any directories other than OS related, if so please copy them to new server.
10. Check on /usr,/opt,/var for database such as Sybase, db2, oracle and any links created. Verify with target host.
11. Closely work with database team to build the filesystem (raw device) for their database dumps.

Client installations

1. Verify if clearcase client is installed  ( ps –ef | grep clearcase or look  for /view  filesystem )
2. Check for mq-series-MQM ( ps –ef | grep mq, pkginfo –l mqm, look for /opt/mqm and /var/mqm
3. Check /opt to see if there are any application/database clients, such as oracle, Sybase, DB2, autosys, pgp..etc.
4. Confirm DB2 client versions with fixpack levels.
5. Verify JAVA versions on old servers, keep SAME java versions on new server, and please make sure to keep the same links as old server. They are very critical and application will fail if they are not copied correctly.
6. Check PERL versions, modules  and PERL path.

Startup Scripts

1. Check /etc/rc2.d and /etc/rc3.d  for start up scripts.
2. Check /etc/init.d for startup scripts.
3. Check /etc/rc0.d and /etc/rc1.d for  kill scripts.
SSH Keys
1. Copy  /etc/ssh/authorized_keys  from old server to new server if there is any.
2. Copy old host keys(.rsa and .dsa) to new server( take backup of existing host keys on new server /etc/ssh).
3. Check the number of keys on old new serverson both servers and they should match.
4. If new key need to be added to the user, do not overwrite, append it.
Quality Check
1. Re-run the rsyncs on all filesystems.
2. Review every possible aspect of os, filesystem, application, database.
Final Rsyncs
1. Stop eTrust/Firewall on both old and new servers and run final rsync with –update option .
2. Verify number of files on each filesystem with ls –lR | wc-l and compare with old server to new server.

DNS change

1. Once everything is verified, shutdown your old host.
2. Coordinate with person who manages DNS to create an alias (cname record) from old host to new host.
3. Once the change is made, reboot your new server
4. Once server is up, use old name to login to the system.
5. Verify your access, your sudo access
6. Check applicaiton, system, and other process
7. Check log to see if you have any errors
8. Once you have verified everything, coordinate with app, database and other team to verify their stuffs.

Next day,

1. Check your email regarding issue with migration.
2. You have something breaking, fix it.
3. If you need to copy something from old host, bring the server by logging to the console and once up, login to the server using ip address.

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