LearnAdmin: March 2010

To Know Which Shell You Are Working

The echo $SHELL will give you the current shell you are working on.

Installing and Configuring Monit Step by Step

install and configure monit

apt-get install monit

Monit Configuration file is /etc/monit/monitrc

Now make the list of services you want to monitor

for example sshd,apache,Mysql

Now for monit web interface the default port number is 2812

Now let us configure the monit

vi /etc/monit/monitrc
--------------------------------------------------------------------------------------------------------------------

set daemon  60    // time interval of the daemon
set logfile syslog facility log_daemon
set mailserver localhost
set mail-format { from: monit@server1.example.com }
set alert root@localhost // mail id to send email alerts
set httpd port 2812 and  // If you want to chang port number change here better leave it default
     SSL ENABLE          // for SSL
     PEMFILE  /var/certs/monit.pem   // SSL certificate location
     allow admin:test                // user name and password Basic Auth

// monitoring sshd

check process sshd with pidfile /var/run/sshd.pid
   start program  "/etc/init.d/ssh start"
   stop program  "/etc/init.d/ssh stop"
   if failed port 22 protocol ssh then restart
   if 5 restarts within 5 cycles then timeout

// monitoring mysql

check process mysql with pidfile /var/run/mysqld/mysqld.pid
   group database
   start program = "/etc/init.d/mysql start"
   stop program = "/etc/init.d/mysql stop"
   if failed host 127.0.0.1 port 3306 then restart
   if 5 restarts within 5 cycles then timeout

// monitoring apache

check process apache with pidfile /var/run/apache2.pid
   group www
   start program = "/etc/init.d/apache2 start"
   stop program  = "/etc/init.d/apache2 stop"


   if failed host www.example.com port 80 protocol http
      and request "/monit/token" then restart

here monit tries to connect www.example.com on port 80 and tries to access a file

/monit/token

the actual location of /monit/token is

/var/www/www.example.com/web/monit/token

as our website document root is

/var/www/www.example.com/web

if monit cannot access this file it means apache is not runnig so it will

restart apache.

Creation of token is given below

   if cpu is greater than 60% for 2 cycles then alert
   if cpu > 80% for 5 cycles then restart
   if totalmem > 500 MB for 5 cycles then restart
   if children > 250 then restart
   if loadavg(5min) greater than 10 for 8 cycles then stop
   if 3 restarts within 5 cycles then timeout

you can add your custom process for 
monitoring here

----------------------------------------------------------------------------------------------------------------

Creation of token

---------------------

mkdir /var/www/www.example.com/web/monit

echo "hello" > /var/www/www.example.com/web/monit/token

Creation of SSL-encrypted monit web interface

-----------------------------------------------------------------
( /var/certs/monit.pem )

openssl req -new -x509 -days 365 -nodes -config ./monit.cnf -out /var/certs/monit.pem -keyout /var/certs/monit.pem
openssl gendh 512 >> /var/certs/monit.pem
openssl x509 -subject -dates -fingerprint -noout -in /var/certs/monit.pem
chmod 700 /var/certs/monit.pem

then we need to configure OpenSSL configuration file to create our certificate
vi /var/certs/monit.cnf

example file is
-------------------------------------------------------------------------------------------

# create RSA certs - Server

RANDFILE = ./openssl.rnd

[ req ]
default_bits = 1024
encrypt_key = yes
distinguished_name = req_dn
x509_extensions = cert_type

[ req_dn ]
countryName = Country Name (2 letter code)
countryName_default = MO

stateOrProvinceName             = State or Province Name (full name)
stateOrProvinceName_default     = Monitoria

localityName                    = Locality Name (eg, city)
localityName_default            = Monittown

organizationName                = Organization Name (eg, company)
organizationName_default        = Monit Inc.

organizationalUnitName          = Organizational Unit Name (eg, section)
organizationalUnitName_default  = Dept. of Monitoring Technologies

commonName                      = Common Name (FQDN of your server)
commonName_default              = server.monit.mo

emailAddress                    = Email Address
emailAddress_default            = root@monit.mo

[ cert_type ]
nsCertType = server

------------------------------------------------------------------------------

enable monit daemon now

/etc/default/monit

in this file set startup =1 and interval for running the monit daemon

example file is below

--------------------------------------------------------------

# Defaults for monit initscript
# sourced by /etc/init.d/monit
# installed at /etc/default/monit by maintainer scripts
# Fredrik Steen 

# You must set this variable to for monit to start
startup=1

# To change the intervals which monit should run uncomment
# and change this variable.
CHECK_INTERVALS=60

---------------------------------------------------------------

now let us start monit

/etc/init.d/monit start

Now point your browser to https://www.example.com:2812/
 (make sure port 2812 is not blocked by your firewall), log in with admin and test

as specified in /etc/monit/monitrc

How to rename temp files in temporary tablespace

SHUTDOWN
STARTUP MOUNT
ALTER DATABASE RENAME FILE 'oldpath' TO 'newfile path';
ALTER DATABASE OPEN;

delete older file

Steps to start the multiple listener in Oracle

$lsnrctl
LSNRCTL>set current DEMO
LSNRCTL> start
LSNRCTL> set current PROD
LSNRCTL> start

How does DNS work step by step

Client enters a domain name (www.domainname.com) into his browser

The browser contacts the Client's ISP for the IP address of the domain name

The ISP first tries to answer by itself using "cached" data.

If the answer is found it is returned. Since the ISP isn't in charge of the DNS, and is just acting as a "dns relay", the answer is marked "non-authoritative"

If the answer isn't found, or it's too old (past the TTL), then the ISP DNS contacts the nameservers for the domain directly for the answer.

If the nameservers are not known, the ISP's looks for the information at the 'root servers', or 'registry servers'. For com/net/org, these start with a.gtld-servers.net.

NOTE: The 'whois' information is never used for DNS, and is often misleading and inaccurate

For More Detaild Explanation Click Here

ZFS file system Step by Step

ZFS stands for Zettabyte File System .

It is designed by Sun Microsystems for the Solaris Operating.

The features of ZFS include support for high storage capacities, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs. ZFS is implemented as open-source software, licensed under the Common Development and Distribution License (CDDL).

Some of the benefits of the ZFS file system:

Filesystem and Volumemanger in one system
Easy administration with only 2 commands - #zpool and #zfs
advanced raid level and functions
snapshots
automatic checksum over all data
128 Bit
automatic shrinking and growing volumes
No RAID cards required, using ZFS built in RAID-Z redundancy. (reduces hardware cost drastically)
Effective and Optimal SnapShots
Compressed Zpools.
Built in NFS/ISCSI/SMB Sharing
Support PNFS for high speed interconnects. (Will use all the 6 GigE ports)

Configuring ZFS

Permitted subcommands are list, iostat, status, online,
offline, scrub, import, and history.

Find version of ZFS

  # kextstat | grep zfs

zpool - configuring zfs storage pools

# zpool create myzfs /disk1 /disk2

# zpool create mypool mirror disk1s1 disk0s1 mirror disk1s2 disk0s2

# mkfile 100m disk1 disk2 disk3 disk5# mkfile 50m disk4
# ls -l disk*
-rw------T   1 root     root     104857600 Sep 11 12:15 disk1
-rw------T   1 root     root     104857600 Sep 11 12:15 disk2
-rw------T   1 root     root     104857600 Sep 11 12:15 disk3
-rw------T   1 root     root     52428800 Sep 11 12:15 disk4
-rw------T   1 root     root     104857600 Sep 11 12:15 disk5

Creating hot spares

when any disk goes down the disk marked as hotspare will

automatically take its functionality after it gets replaced.

#  zpool create pool mirror disk0 disk1 spare disk2 disk3

These spares can be across multiple pools and can be added

with zpool add  and removed with zpool remove

Automated Installation of MySQL without asking password

is your the installation process pops up a blue dialog asking for a root password ?? want to make automated

without the asking of password then

First give this two commands

echo "mysql-server mysql-server/root_password select (password omitted)" | debconf-set-selections

echo "mysql-server mysql-server/root_password_again select (password omitted)" | debconf-set-selections

Then the installation will not ask for passowrd then continue installation.

apt-get install mysql-client-5.1 mysql-server-5.1 -y

LearnAdmin

Labels

To Know Which Shell You Are Working

Installing and Configuring Monit Step by Step

How to rename temp files in temporary tablespace

Steps to start the multiple listener in Oracle

Veritas Storage Area Network Concepts step by step material download

Veritas Disaster Recovery Planning step by step material download

Veritas Backup and Restore Step by Step Material download

Storage Virtulization Concepts Step by Step material download

High Availability Concepts Step by Step Download Material

EMC Training material download

How does DNS work step by step

ZFS file system Step by Step

Some of the benefits of the ZFS file system:

Automated Installation of MySQL without asking password

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