July 2025
M T W T F S S
 123456
78910111213
14151617181920
21222324252627
28293031  

Categories

July 2025
M T W T F S S
 123456
78910111213
14151617181920
21222324252627
28293031  

Local YUM server installation and configuration – RHEL7

The Yellowdog Updater, Modified (yum) is an open-source command-line package-management utility for Linux operating systems using the RPM Package Manager. Though yum has a command-line interface, several other tools provide graphical user interfaces to yum functionality.

   Basically we will YUM to resolve the dependencies automatically and install them, Using YUM repository you can lot of time to install the packages and its dependencies.


To build your local YUM server first you have copy all the packages from Installation media (RHEL 7 DVD).

Make one directory to copy the RPM’s

~]#mkdir /rpms
~]#cp -v /run/media/root/RHEL7/Packges/* /rpms

After completion of copying the packages to /rpms directory.

install createrepo RPM
~]# rpm -ivh createrepo-0.9.9-23.el7.noarch.rpm

After installation of above package edit the yum configuration file then add the following configuration lines.

~]# cat /etc/yum.repos.d/redhat.repo
[rhel7-tutorial]
name=rhel7-tutorial
baseurl=file:///rpms
gpgcheck=0
enabled=1

now create repository using below command

~]#createrepo /rpms/

OR
 
you can also use

Change the directory path to /rpms then run below command

rpms]#createrepo –database /rpms/

 

 

download

 

 

Verify your packages using ~]#yum list all

to know about any package and its usage

~]#yum info dhcp-common

 

 

 

download (1)

 

download (2)

earch for particular package name so that it will give you list of packages which are available in the repository

~]#yum list installed
Check your installed packages using above command

~]#yum remove PackageName
Remove mentioned package and its dependencies from server

~]#yum list extras

This command lists any installed package which no longer appears in any of your enabled repositories. Useful for finding packages which linger between upgrades or things installed not from a repo

~]#yum list obsoletes

This command lists any obsoleting relationships between any available package and any installed package.

~]#yum list updates

This command lists any package in an enabled repository which is an update for any installed package.

~]#yum list recent

This command lists any package added to any enabled repository in the last seven(7) days.

 

~]#yum clean packages

This cleans up any cached packages in any enabled repository cache directory.

 

~]#yum clean metadata

This cleans up any xml metadata that may have been cached from any enabled repository.

~]#yum clean dbcache

Yum will create or download some sqlite database files as part of its normal operation. This command clean up the cached copies of those from any enabled repository cache.

~]#yum clean all

Clean all cached files from any enabled repository. Useful to run from time to time to make sure there is nothing using unnecessary space.

 

August 7th, 2016 | Category: Centos RHEL 7 | Leave a comment

BLACKLIST AND WHITELIST FOR ZIMBRA SPAM FILTER

BLACKLIST AND WHITELIST FOR ZIMBRA SPAM FILTER

 

gin to console as “root” user. Edit the amavisd config file /opt/zimbra/conf/amavisd.conf.in,

Add 2 lines:

read_hash(\%whitelist_sender, '/opt/zimbra/conf/whitelist');
read_hash(\%blacklist_sender, '/opt/zimbra/conf/blacklist');

Create the list files:

#vi /opt/zimbra/conf/whitelist
example.com
EOT

#vi /opt/zimbra/conf/blacklist
spammer@example.com
EOT


Restart Service:


#su - zimbra -c 'zmamavisdctl restart'


						
August 7th, 2016 |  Category: ZIMBRA | Leave a comment 
		
	
						
		
								

						
				
				RHEL 7 Extras
				




RHEL 7 Extras




Introduction of Docker
Docker is an open source project that automates the deployment of applications inside Linux Containers, and provides the capability to package an application with its runtime dependencies into a container.




Device Hotplug Removed
While RHEL 5/6 has device hotplug support (udev rule that runs the ifup script for newly created devices), it has been disabled for RHEL 7 since it can result in race conditions when initializing newly found.




No 32 Bit ISO Image
No 32 bit ISO for download. Red Hat Enterprise Linux 7 will only provide 64-bit ISO’s, thus allowing only a 64-bit operating environment. RHEL 7 will not natively support 32-bit hardware.




MemAvailable Added to meminfo
A new entry to the /proc/meminfo file has been introduced to provide the MemAvailable field. MemAvailable provides an estimate of how much memory is available for starting new applications, without swapping. However, unlike the data provided by the Cache or Free fields, MemAvailable takes into account page cache and also that not all reclaimable memory slabs will be reclaimable due to items being in use.




New Ruby and Python Versions
Red Hat Enterprise Linux 7 provides the latest Ruby version, 2.0.0 and Python 2.7.5.




OpenJDK7 Made Default
Red Hat Enterprise Linux 7 features OpenJDK7 as the default Java Development Kit (JDK) and Java 7 as the default Java version.




More Powerful NetworkManager

NetworkManager has been significantly enhanced to configure and monitor all the networking features for enterprise class servers and for desktop applications.


For the enterprise data centers, NetworkManager can be used for tasks such as basic networking configuration, network teaming, configuring virtual LANs, bridges, bonds, IPv6, VPNs, assigning interfaces to firewall zones, and others. For desktop servers it can manage wired and wireless networks and VPNs.





Support for 40 Gigabit NICs
Red Hat Enterprise Linux 7 supports 40 Gigabit network interface controllers (NICs) from multiple hardware partners. This provides support for 40 Gigabit Ethernet link speeds enabling faster network communication for applications and systems. Note that the ethtool utility will report interface link speeds up to 40Gb data rates.




No RHN Classic
RHN Classic is not supported in RHEL7. Older versions supported different subscription management method being used. Red Hat Subcription Management is the only one used by RHEL 7.




OpenSSH – Multiple Required Authentications
Red Hat Enterprise Linux 7 supports multiple required authentications in SSH protocol version 2 using the AuthenticationMethods option. This option lists one or more comma-separated lists of authentication method names. Successful completion of all the methods in any list is required for authentication to complete.




Minimum Disk Space for Installation of RHEL7
Red Hat Enterprise Linux 7 now requires at least 1 GB of disk space to install. However, Red Hat recommends a minimum of 5 GB of disk space for all supported architectures.




Implementation of tmpfs file system
Red Hat Enterprise Linux 7 offers the ability to use /tmp as a mount point for a temporary file storage system (tmpfs).


When enabled, this temporary storage appears as a mounted file system, but stores its content in volatile memory instead of on a persistent storage device. No files in /tmp are stored on the hard drive except when memory is low, in which case swap space is used. This means that the contents of /tmp are not persisted across a reboot.





New Logging Framework
Red Hat Enterprise Linux 7 introduces a new logging daemon, journald, as part of the move to systemd.


journald captures the following types of message for all services:


– syslog messages

– kernel messages

– initial RAM disk and early boot messages

– messages sent to standard output and standard error output.





Changes to mount options
Unlike ext3 and ext4, the XFS file system enables the user_xattr and acl mount options by default. Ext3 and ext4 file systems do not enable these attributes by default.






						
August 7th, 2016 |  Category: Centos RHEL 7 | Leave a comment 
		
	
						
		
								

						
				
				RHEL7 and 6 difference
				




Features
RHEL 7
RHEL 6




Default File System
XFS
EXT4




Kernel Version
3.10.x-x kernel
2.6.x-x Kernel




Kernel Code Name
Maipo
Santiago




General Availability Date of First Major Release
2014-06-09 (Kernel Version 3.10.0-123)
2010-11-09 (Kernel Version 2.6.32-71)




First Process
systemd (process ID 1)
init (process ID 1)




Runlevel
runlevels are called as “targets” as shown below:


runlevel0.target -> poweroff.target

runlevel1.target -> rescue.target

runlevel2.target -> multi-user.target

runlevel3.target -> multi-user.target

runlevel4.target -> multi-user.target

runlevel5.target -> graphical.target

runlevel6.target -> reboot.target


/etc/systemd/system/default.target (this by default is linked to the multi-user target)

Traditional runlevels defined :


runlevel 0

runlevel 1

runlevel 2

runlevel 3

runlevel 4

runlevel 5

runlevel 6


and the default runlevel would be defined in /etc/inittab file.

/etc/inittab





Host Name Change
In Red Hat Enterprise Linux 7, as part of the move to the new init system (systemd), the hostname variable is defined in /etc/hostname.
In Red Hat Enterprise Linux 6, the hostname variable was defined in the /etc/sysconfig/network configuration file.




Change In UID Allocation
By default any new users created would get UIDs assigned starting from 1000.


This could be changed in /etc/login.defs if required.

Default UID assigned to users would start from 500.


This could be changed in /etc/login.defs if required.





Max Supported File Size
Maximum (individual) file size = 500TB

Maximum filesystem size = 500TB


(This maximum file size is only on 64-bit machines. Red Hat Enterprise Linux does not support XFS on 32-bit machines.)

Maximum (individual) file size = 16TB

Maximum filesystem size = 16TB


(This maximum file size is based on a 64-bit machine. On a 32-bit machine, the maximum files size is 8TB.)





File System Check
“xfs_repair”


XFS does not run a file system check at boot time.

“e2fsck”


File system check would gets executed at boot time.





Differences Between xfs_repair & e2fsck

“xfs_repair”


– Inode and inode blockmap (addressing) checks.

– Inode allocation map checks.

– Inode size checks.

– Directory checks.

– Pathname checks.

– Link count checks.

– Freemap checks.

– Super block checks.


“e2fsck”


– Inode, block, and size checks.


– Directory structure checks.


– Directory connectivity checks.


– Reference count checks.


– Group summary info checks.





Difference Between xfs_growfs & resize2fs
“xfs_growfs”


xfs_growfs takes mount point as arguments.

“resize2fs”


resize2fs takes logical volume name as arguments.





Change In File System Structure
/bin, /sbin, /lib, and /lib64 are now nested under /usr.
/bin, /sbin, /lib, and /lib64 are usually under /




Boot Loader
GRUB 2

Supports GPT, additional firmware types, including BIOS, EFI and OpenFirmwar. Ability to boot on various file systems (xfs, ext4, ntfs, hfs+, raid, etc)		
GRUB 0.97




KDUMP
RHEL7 supports kdump on large memory based systems up to 3 TB
Kdump doesn’t work properly with large RAM based systems.




System & Service Manager
“Systemd”


systemd is a system and service manager for Linux, and replaces SysV and Upstart used in previous releases of Red Hat Enterprise Linux. systemd is compatible with SysV and Linux Standard Base init scripts.

Upstart




Enable/Start Service
For RHEL 7, the systemctl command replaces service and chkconfig.


– Start Service : “systemctl start nfs-server.service”.


– Enable Service : To enable the service (example: nfs service ) to start automatically on boot : “systemctl enable nfs-server.service”.


Although one can still use the service and chkconfig commands to start/stop and enable/disable services, respectively, they

are not 100% compatible with the RHEL 7 systemctl command (according to redhat).

Using “service” command and “chkconfig” commands.


– Start Service : “service start nfs” OR “/etc/init.d/nfs start”


– Enable Service : To start with specific runlevel : “chkconfig –level 3 5 nfs on”





Default Firewall
“Firewalld (Dynamic Firewall)”


The built-in configuration is located under the /usr/lib/firewalld directory. The configuration that you can customize is under the /etc/firewalld directory. It is not possible to use Firewalld and Iptables at the same time. But it is still possible to disable Firewalld and use Iptables as before.

Iptables




Network Bonding
“Team Driver”


-/etc/sysconfig/network-scripts/ifcfg-team0

– DEVICE=”team0”

– DEVICETYPE=”Team”

“Bonding”


-/etc/sysconfig/network-scripts/ifcfg-bond0

– DEVICE=”bond0”





Network Time Synchronization
Using Chrony suite (faster time sync compared with ntpd)
Using ntpd




NFS
NFS4.1

NFSv2 is no longer supported. Red Hat Enterprise Linux 7 supports NFSv3, NFSv4.0, and NVSv4.1 clients.		
NFS4




Cluster Resource Manager
Pacemaker
Rgmanager




Load Balancer Technology
Keepalived and HAProxy
Piranha




Desktop/GUI Interface
GNOME3 and KDE 4.10
GNOME2




Default Database
MariaDB is the default implementation of MySQL in Red Hat Enterprise Linux 7
MySQL




Managing Temporary Files
RHEL 7 uses systemd-tmpfiles (more structured, and configurable, method to manage tmp files and directories).
Using “tmpwatch”











						
August 7th, 2016 |  Category: Centos RHEL 7 | Leave a comment 
		
	
						
		
								

						
				
				CentOS 7 / RHEL firewalld settings
				
CentOS 7 / RHEL firewalld settings


CentOS 7 has adopted firelwalld by default over the previous iptables, which will require some new steps to configure your firewall:


# new CentOS/RHEL 7 Firewall:

	(see https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Security_Guide/sec-Using_Firewalls.html )


# create a new service e.g. for webmin:


$ cat /etc/firewalld/services/webmin.xml





  Webmin

  Server admin service. Restrict access and do not leave running.
  



# add service to zone:


nano /etc/firewalld/zones/public.xml

# OR

$ firewall-cmd –permanent –zone=public –add-service=webmin


# reload to add:


$ firewall-cmd –reload


# check:

$ firewall-cmd –zone=public –list-all


## apache / httpd:

$ firewall-cmd –permanent –add-service=http

$ firewall-cmd –permanent –add-service=https

$ systemctl restart firewalld


						
August 6th, 2016 |  Category: Centos RHEL 7 | Leave a comment 
		
	
						
		
								

						
				
				convert a PFX to a seperate .key/.crt file
				
So after you installed OpenSSL you can start it from it’s Bin folder. I’d like to put OpenSSL\Bin in my path so I can start it from any folder. Fire up a command prompt and cd to the folder that contains your .pfx file. First type the first command to extract the private key:


openssl pkcs12 -in [yourfile.pfx] -nocerts -out [keyfile-encrypted.key]


What this command does is extract the private key from the .pfx file. Once entered you need to type in the importpassword of the .pfx file.  This is the password that you used to protect your keypair when you created your .pfx file.  If you cannot remember it anymore you can just throw your .pfx file away, cause you won’t be able to import it again, anywhere!.  Once you entered the import password OpenSSL requests you to type in another password, twice!. This new password will protect your .key file.


Now let’s extract the certificate:


openssl pkcs12 -in [yourfile.pfx] -clcerts -nokeys -out [certificate.crt]


Just press enter and your certificate appears.


Now as I mentioned in the intro of this article you sometimes need to have an unencrypted .key file to import on some devices.  I probably don’t need to mention that you should be carefully. If you store your unencrypted keypair somewhere on an unsafe location anyone can have a go with it and impersonate for instance a website or a person of your company.  So always be extra careful when it comes to private keys! Just throw the unencrypted keyfile away when you’re done with it, saving just the encrypted one.


The command:


openssl rsa -in [keyfile-encrypted.key] -out [keyfile-decrypted.key]


Again you need to enter an import password. This time you need to enter the new password that you created in step 1.  After that you’re done. You decrypted your private key. In the folder you ran OpenSSL from you’ll find the certifcate (.crt) and the two private keys (encrypted and unencrypted).


Update 07-07-2014:


In some cases you might be forced to convert your private key to PEM format. You can do so with the following command:


openssl rsa -in [keyfile-encrypted.key] -outform PEM -out [keyfile-encrypted-pem.key]


dditionally to


openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.cer

openssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain.key


openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.cer

openssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain_encrypted.key

openssl rsa -in domain_encrypted.key -out domain.key


						
August 3rd, 2016 |  Category: SSL | Leave a comment 
		
	
						
		
								

						
				
				OpenSSL command reference
				
OpenSSL command reference

General OpenSSL commands

commands to generate CSRs, Certificates, Private Keys and other tasks.


Generate a new private key and matching certificate signing request (Unix) 


openssl req -out CSR.csr -pubkey -new -keyout privateKey.key

Generate a new private key and matching certificate signing request (Windows)


openssl req -out CSR.csr -pubkey -new -keyout privateKey.key -config .shareopenssl.cmf

Generate a certificate signing request for an existing private key


openssl req -out CSR.csr -key privateKey.key -new

Generate a certificate signing request based on an existing x509 certificate


openssl x509 -x509toreq -in MYCRT.crt -out CSR.csr -signkey privateKey.key

Decrypt private key


openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout privateKey.key -out certificate.crt

Remove a passphrase from a private key


openssl rsa -in privateKey.pem -out newPrivateKey.pem

Checking commands

Check a certificate signing request 


openssl req -text -noout -verify -in CSR.csr

Check a private key


openssl rsa -in privateKey.key -check

Check a certificate


openssl x509 -in certificate.crt -text -noout

Check a PKCS#12 keystore


openssl pkcs12 -info -in keyStore.p12

Debugging commands

commands to debug a SSL connection


Check the MD5 hash of the public key


openssl x509 -noout -modulus -in certificate.crt | openssl md5

openssl rsa -noout -modulus -in privateKey.key | openssl md5

openssl req -noout -modulus -in CSR.csr | openssl md5

Check an SSL connection. All certificates (also intermediates) should be shown


openssl s_client -connect https://www.paypal.com:443

Converting commands

Use the following commands to convert certificates and keys to different formats to make them compatible with specific types of servers or software. For example, convert a normal PEM file that would work with Apache to a PFX (PKCS#12) file for use with Tomcat or IIS.


Convert DER (.crt .cer .der) to PEM


openssl x509 -outform der -in certificate.cer -out certificate.der


openssl x509 -inform der -in certificate.der -out certificate.pem

Convert PEM to DER


openssl x509 -outform der -in certificate.pem -out certificate.der

Convert PKCS#12 (.pfx .p12) to PEM containing both private key and certificates


openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes

    add -nocerts for private key only; add -nokeys for certificates only

Convert (add) a seperate key and certificate to a new keystore of type PKCS#12


openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.cr


						
August 3rd, 2016 |  Category: SSL | Leave a comment 
		
	
						
		
								

						
				
				Configuring automatic startup of Oracle Database under systemd on RHEL 7/OEL 7/CentOS 7
				
Configuring automatic startup of Oracle Database under systemd on RHEL 7/OEL 7/CentOS 7

There are several methods how to start Oracle Database automatically during/after OS boot. You can use Oracle CRS, other clusterware or init implemented in Linux. Starting RHEL 7 SysV init has been replaced by systemd or simply said systemd is the new init system.


In these days not only group of Linux users became polarized but also whole Linux world became polarized as well. Mostly Redhat based distributions have adopted systemd, other distributions are reluctant to implement systemd and either are continuing to use SysV init or migrated to another solutions e.g. Upstart. Despite this fact most of the Oracle certified Linux distributions (such as Redhat or SuSE and their (even not certified) clones) are using the systemd.


This post briefly shows how to configure systemd service for automatic start of Oracle Databases and Listener and these steps are applicable for Redhat Enterprise Linux 7, Oracle Enterprise Linux 7, CentOS 7 or SuSE Linux Enteprise Server 12 and Fedora 15 (or later).


Typically systemd startup configuration consists of two parts:


unit file – using “.service” suffix (in case of service), typically stored in /usr/lib/systemd/system or /etc/systemd/system directory for units provided by installed packages or /usr/lib/systemd/user or /etc/systemd/user directory for units installed by administrator

environment file (optional) – typically stored in /etc/sysconfig directory on RHEL and it’s clones. We don’t need it in our case.

Creating the unit for automatic startup/shutdown of Oracle Database manually


Logon as root user create and edit /etc/systemd/system/oracle-rdbms.service and add following content:


# /etc/systemd/system/oracle-rdbms.service

#   Invoking Oracle scripts to start/shutdown Instances defined in /etc/oratab

#   and starts Listener


[Unit]

Description=Oracle Database(s) and Listener

Requires=network.target


[Service]

Type=forking

Restart=no

ExecStart=/opt/oracle/12102/bin/dbstart /opt/oracle/12102

ExecStop=/opt/oracle/12102/bin/dbshut /opt/oracle/12102

User=oracle


[Install]

WantedBy=multi-user.target

 Note that this configuration assumes that our ORACLE_HOME is /opt/oracle/12102. It’s recommended to use PIDFile while using “forking” type but we don’t need it. As you can see well known scripts (shipped with Oracle Database) are executed for startup/shutdown using path to Oracle Home in order to specify the Oracle Home for Listener process. As shown these scripts are executed under “oracle” user account/privileges. More over service can be started once network is cofigured (started) and service starts in multi-user level (more less equivalent of runlevel 3 in SysV init)


Now we have to reload systemd in order to register unit file (as root) and enable the service.


systemctl daemon-reload

systemctl enable oracle-rdbms


 So, now the startup service should be created and enabled but to be sure we can check it by following command (Note: first line is OS command, other lines is the output):


systemctl status oracle-rdbms

oracle-rdbms.service – Oracle Database(s) and Listener

   Loaded: loaded (/etc/systemd/system/oracle-rdbms.service; enabled)

According to output our service is enabled succesfully and should be started on next OS boot. To start the service without reboot of machine you can use following command:


systemctl start oracle-rdbms


Creating the unit for automatic startup/shutdown of Oracle Database using script


I have created a simple script which automatically performs above tasks for creating and enabling startup service. This scripts contains simple checks (as I’ve tried to make the script bulletproof), then lists available Oracle homes that exist on OS and then asks to specify Oracle home from which the Listener will be started. Note that it’s important to specify Oracle home for the highest version of Oracle software as Listener will be handling connections for all Oracle homes.


#!/usr/bin/bash


# This script configures systemd startup service for Oracle Databases and Listener

# Ivan Kartik http://ivan.kartik.sk


if [ `whoami` != “root” ]; then

   echo “root login required!”

   exit

fi


if [ `uname -s` != “Linux” ]; then

   echo “This is not Linux!”

   exit

fi


if [ `ps -e|grep ” 1 ?”|cut -d ” ” -f15` != “systemd” ]; then

   echo “Systemd is not present, use Init scripts instead!”

   exit

fi


echo “List of existing Oracle Homes:”

echo “——————————”

cat `cat /etc/oraInst.loc|grep inventory_loc|cut -d ‘=’ -f2`/ContentsXML/inventory.xml|grep “HOME NAME”|cut -d ‘”‘ -f 4

echo 


echo “Enter ORACLE_HOME of Oracle Listener [$ORACLE_HOME]:”

read NEWHOME


case “$NEWHOME” in

     “”)         ORAHOME=”$ORACLE_HOME” ;;

     *)          ORAHOME=”$NEWHOME” ;;

esac


if [ -z $ORAHOME ]; then

   echo “Error: Missing value!”

   exit

fi


if [ -f $ORAHOME/bin/lsnrctl ]; then

   echo ‘# /etc/systemd/system/oracle-rdbms.service

# Ivan Kartik http://ivan.kartik.sk

#   Invoking Oracle scripts to start/shutdown Instances defined in /etc/oratab

#   and starts Listener


[Unit]

Description=Oracle Database(s) and Listener

Requires=network.target


[Service]

Type=forking

Restart=no

ExecStart=’$ORAHOME’/bin/dbstart ‘$ORAHOME’

ExecStop=’$ORAHOME’/bin/dbshut ‘$ORAHOME’

User=oracle


[Install]

WantedBy=multi-user.target’ > /etc/systemd/system/oracle-rdbms.service


    systemctl daemon-reload

    systemctl enable oracle-rdbms

    echo “Done! Service oracle-ordbms has been configured and will be started during next boot.”

    echo “If you want to start service now, execute: systemctl start oracle-rdbms”

else

   echo “Error: No Listener script under specified ORACLE_HOME: $ORAHOME”

   exit

fi


You either can copy/paste this code or download here: http://ivan.kartik.sk/scripts/oracle_systemd_service.sh


Final check of service and started databases (Note: Output from systemctl status has been shortened):


# cat /etc/oratab |grep :Y

ORA12CR1:/opt/oracle/12102:Y

ORA11GR2:/opt/oracle/11204:Y


# systemctl status oracle-rdbms

oracle-rdbms.service – Oracle Database(s) and Listener

   Loaded: loaded (/etc/systemd/system/oracle-rdbms.service; enabled)

   Active: active (running) since Mon 2015-11-15 14:51:13 CET; 54s ago

  Process: 425 ExecStart=/opt/oracle/12102/bin/dbstart /opt/oracle/12102 (code=exited, status=0/SUCCESS)

   CGroup: /system.slice/oracle-rdbms.service

           ?? 452 /opt/oracle/12102/bin/tnslsnr LISTENER -inherit

           ??1155 ora_pmon_ORA12CR1

           ??1171 ora_vktm_ORA12CR1

           ??1177 ora_gen0_ORA12CR1

           ??1181 ora_mman_ORA12CR1

           ??1183 ora_diag_ORA12CR1

           ??1185 ora_dbrm_ORA12CR1

           ??1195 ora_ckpt_ORA12CR1

           ??1197 ora_smon_ORA12CR1

           ??1199 ora_reco_ORA12CR1

           ??1201 ora_lreg_ORA12CR1

           ??1289 ora_mman_ORA11GR2

…..

           ??1291 ora_dbw0_ORA11GR2

           ??1293 ora_lgwr_ORA11GR2

           ??1295 ora_ckpt_ORA11GR2

           ??1297 ora_smon_ORA11GR2

           ??1299 ora_reco_ORA11GR2

           ??1301 ora_mmon_ORA11GR2

           ??1303 ora_mmnl_ORA11GR2

           ??1350 ora_qmnc_ORA11GR2

           ??1450 ora_q001_ORA11GR2


Nov 15 14:50:57 oel01 dbstart[425]: Processing Database instance “ORA12CR1”: log file /opt/oracle/12102/startup.log

Nov 15 14:51:07 oel01 dbstart[425]: Processing Database instance “ORA11GR2”: log file /opt/oracle/11204/startup.log

Nov 15 14:51:13 oel01 systemd[1]: Started Oracle Database(s) and Listener.

For little comparison of difference commands or usage regarding SysV init and systemd, here is very nice cheat sheet created by guys from Linoxide.com it’s downloadable


						
August 3rd, 2016 |  Category: Centos RHEL 7, Oracle | Leave a comment 
		
	
						
		
								

						
				
				IPMI
				
IPMI ( Intelligent Platform Management Interface ) : It  is a remote hardware health monitoring and management system that defines interfaces for use in monitoring the physical health of servers.


IPMI provides a way to monitor & manage a server system that may be powered off or unresponsive by using a network connection to the hardware rather than to an OS.


IPMI functions independently of the OS to allow system admins to manage a system remotely in the absence of an operating system .IPMI can work in any of three situations:

Situation 1 : Your remote server is down, the Operating System is not booting up and you need to check what happened remotely and you need to start the machine, again remotely (without accessing the physical hardware).


Situation 2 : You are on a weekend holiday and you received email that one node in cluster is not responding. You need to find what happened and might need to fence (or reboot) the machine, remotely.


Situation 3 : You need a detailed report on server health.


The primary IPMI features include:


Monitoring (supervision of the hardware)

Recovery Control (Recover/Restart the server)

Logging (protocol “out-of-range” states for the hardware)

Inventory (list of hardware inventory)

IPMI provides these four functions independently from the server’s CPU, BIOS and operating system. The platform management features are also available when the server has been shutdown (as long as at least one server power supply has power).


						
August 3rd, 2016 |  Category: Centos RHEL 7 | Leave a comment 
		
	
						
		
								

						
				
				dynamic date value in shell scripts
				
dynamic date value in shell scripts

using a variable – easier to read in scripts:

NOW=$(date +”%Y%m%d%H%M%S”)

echo “bar” > “$NOW”foobar.txt


one-line, equivalent to above:

echo “bar” > $(date +”%Y%m%d%H%M%S”)foobar.txt


alternate single-line format:

echo “bar” >> $(date “+myfile%Y%m%d.txt”)


man strftime to see formatting values


						
August 3rd, 2016 |  Category: Shell | Leave a comment 
		
	
						
	
					

			
« Newer Entries  
  Older Entries »