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Month: December 2017

What is Linux Software, yum and rpm ?

What is Linux Software? It is called a Package It is a file with extension “.rpm” Naming convention of the file is as follows <name> – <version> – <release>.<architecture>.rpm Eg: ftp-0.17-51.1.rl6.i686.rpm Package name: ftp Version: 0.17 Release: 51.1.el6 (el5,rhl9,fc4,suse100)   Where to get rpm from? net pbone.net   What is rpm database? It is a list of files stored in /var/lib/rpm It contains information of all packages, groups installed on the system   What is a yum repository? It is a directory on any server which contains all rpm packages and its dependency information Yum command downloads the packages from this server and installed on local machine Location of this server is stored in a special file under /etc/yum.repos.d/   What is a yum cache? It is a directory (on local) where information obtained from the yum repository is stored for better performance The default locations of this directory is /var/cache/yum It can be changed by modifying /etc/yum.conf   What happens when we install a package? A list of dependent packages is obtained from the yum repository A check is made to find out if all dependent packages are installed or not Dependent packages are installed first Required packages are installed later What if any packages are installed, multiple files are extracted from the packages and copied to various directories with proper file permissions and ownership. The rpm database...

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Linux Network Configuration Command Line

Network Setup Steps: Setup IP Address Setup Gateway Setup NetMask Name Resolution using /etc/hosts Name Resolution using DNS Setup Hostname   Related Commands: ip route ip addr ifconfig hostname ping dig service Related Files: /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network /etc/resolv.conf /etc/hosts Eg: # cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 BOOTPROTO=dhcp ONBOOT=yes TYPE=Ethernet USERCTL=yes PEERDNS=yes   Help-Notes for above configuration: ONBOOT=yes                                    // when host is booted this configuration will be set BOOTPROTO=none/DHCP           //DHCP – Automatically IP Address set from the router/network //NONE – If you want to define manual IP address DNS1=<your router DNS IP>       //Used for Name Resolution (IP-to-Name vice versa) GATEWAY=<Router Private IP> //This Define from where network traffic will flow from one N/W to other N/w   After Network Configuration restart the service: $ service network restart If you don’t have DNS Server in your Organization: You can do the entry in /etc/hosts do the entry of your hostname and IP address. How it works: When you ping to your own machine with hostname, first it will go to your /etc/hosts file it will search hostname if it found the hostname then the IP Address is found from their and ping command start working(getting response)   What to do entry in Host file: <your machine ip> <FQDN> <your hostname>                  //remove “<>” this. Eg: 172.168.8.12                sshinde@rhel.com         sshinde   How to Set hostname: To change hostname permanently goto below file: Vi /etc/sysconfig/network Even...

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Cloud Price Comparison Azure | AWS | Google

If the price is a key concern for deciding between top IaaS [Infrastructure as a Service] Provider: Check out below chart regarding Cloud Price Comparison: AWS vs. Azure vs. GCP [Google Cloud Platform] for Linux and Windows instances of various sizes and commitment contracts and to make the charts a little easier to read: Lowest cost in each category is green. Second lowest is yellow. Most expensive is pink. Note this is only the overview this may change and we referred this cloud price comparison from...

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IBM AIX SysAdmin Activities

Monitoring Tools: Nagios/Zabbix/Manual Bash Scripts which is automated for monitoring complete server. Manual check commands: $ vmstat: Run queue, virtual memory statics, paging CPU $ iostat: monitor system input/output (I/O) devices (physical and logical) that are mounted. $ netstat: To monitor network statics $ ps: statistics and status information about processes $ nmon: show local system statistics in interactive mode and records system statistics in recording mode $ topas: shows pid, nice value, user, ppid, cmd, CPU use, memory use, time. Health Checkup: H/W Check – $ prtconf Display output with System info / Server info / N/W info / Paging Space / Memory / I/O. System Uptime – $uptime Shows when the system is started, update every 1, 5, 15 min intervals and which user are login. Load Average Power Backup Failure Troubleshooting: Checking Tickets on Portal / on mails. FileSystem Related like no space in “ /, var, usr, opt” FS, FS corrupt, FS creation and mount. Disk related like extending disk in VG, extending LV, Assigning Luns for Database User etc. Networking related activity like Network Slowdown, ether channel issue etc… User and Group Administration task like password failure, user creation, password assigning [this activity can be done by sudo user/admin user (maximum time begin admin user)] or rarely via root user. Remote session Issues Check cron jobs executed successfully. Pseudo user credential activity (Optional) IBM...

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