int questions

By OK -
Probably the simplest and most common way to do this would be by using the command:

tail -F $LOGFILE

-------------
How To check Memory stats and CPU stats ?

Ans:  Using ‘free’ & ‘vmstat’ command we can display the physical and
virtual memory statistics respectively.With the help of ‘sar’ command we see the CPU utilization & other stats.
-------------
Why is LVM is required ?
Ans: LVM stands for Logical Volume Manager , to resize filesystem’s size online we required LVM partition in Linux.
Size of LVM partition can be extended and reduced using the lvextend & lvreduce commands respectively.
-------------
How to create partition from the raw disk ?
Ans: Using fdisk utility we can create partitions from the raw disk.Below are the steps to create partition from the raw dsik :
– fdisk  /dev/hd* (IDE) or /dev/sd* (SCSI)
– Type n to create a new partition
–  After creating partition , type w command to write the changes to the partition table.
-------------
How to share a directory using nfs ?
Ans: To share a directory using nfs , first edit the configuration file ‘/etc/exportfs’ , add a entry like
‘/<directory-name>  <ip or Network>(Options)’ and then restart the nfs service.
-------------
SMTP          25
DNS            53
FTP             20 (data transfer) , 21 ( Connection established)
DHCP         67/UDP(dhcp server) , 68/UDP(dhcp client)
SSH            22
Squid         3128
-------------
How to check default route and routing table ?
Ans: Using the Commands ‘netstat -nr’ and ‘route -n’ we can see the default route and routing tables.
-------------
How to check which ports are listening in my Linux Server ?
Asn:  Use the Command ‘netstat –listen’ and ‘lsof -i’
-------------
How to upgrade Kernel in Linux ?
Ans: We should never upgrade Linux Kernel , always install the new New kernel using rpm
command because upgrading a kenel can make your linux box in a unbootable state.
-------------
On Unix and Unix-like computer operating systems, a zombie process or defunct process is a process that has completed execution (via the exit system call) but still has an entry in the process table
Zombie processes should not be confused with orphan processes: an orphan process is a process that is still executing, but whose parent has died.
To remove zombies from a system, the SIGCHLD signal can be sent to the parent manually, using the kill command.
-------------
There are three types of port forwarding with SSH:

Local port forwarding: connections from the SSH client are forwarded via the SSH server, then to a destination server

Remote port forwarding: connections from the SSH server are forwarded via the SSH client, then to a destination server

Dynamic port forwarding: connections from various programs are forwarded via the SSH client, then via the SSH server, and finally to several destination servers
-------------
Using the command ‘vgcfgrestore‘ we can recover deleted LVM partitions. Linux keeps the backup copies of lvm configuration  in the/etc/lvm/archive directory.
-------------
Example of searching files with size between 100 kilobytes and 500 kilobytes.
find . -size +100k -a -size -500k
----
Note that -iname is not in the standard and may not be supported by all implementations.
find . -iname 'MyFile*'
----

Comments

Post a Comment

Popular posts from this blog

HAproxy logging

By OK -
ubuntu@ubuntu:/etc/haproxy$ cat /etc/rsyslog.d/haproxy.conf # Create an additional socket in haproxy's chroot in order to allow logging via # /dev/log to chroot'ed HAProxy processes $ModLoad imudp $UDPServerRun 514 local0.* -/var/log/haproxy-0.log local1.* -/var/log/haproxy-1.log ### keep logs in localhost ## $AddUnixListenSocket /var/lib/haproxy/dev/log ------------------- ubuntu@ubuntu:/etc/haproxy$ cat /etc/haproxy/haproxy.cfg global chroot /var/lib/haproxy user haproxy group haproxy log 127.0.0.1   local0         log 127.0.0.1   local1 notice daemon frontend www     bind 192.168.40.128:8282    # haproxy public IP     default_backend as-backend    # backend used backend as-backend    balance leastconn    mode http  server as1 192.168.40.128:8082 check    # application srv 1 defaults log ...
Read more

teamcity Automatic Agent Start under Linux

By OK -
Automatic Agent Start under Linux To run agent automatically on the machine boot under Linux, configure daemon process with the  agent.sh start  command to start it and  agent.sh stop  command to stop it. Refer to an example procedure below: 1. Navigate to the services start/stop services scripts directory: cd /etc/init.d/ 2. Open the build agent service script: sudo vim buildAgent 3. Paste the following into the file : #!/bin/sh ### BEGIN INIT INFO # Provides: TeamCity Build Agent # Required-Start: $remote_fs $syslog # Required-Stop: $remote_fs $syslog # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: Start build agent daemon at boot time # Description: Enable service provided by daemon. ### END INIT INFO #Provide the correct user name: USER="agentuser" case "$1" in start) su - $USER -c "cd BuildAgent/bin ; ./agent.sh start" ;; stop) su - $USER -c "cd BuildAgent/bin ; ./agent....
Read more

NFS mount add in fstab _netdev instead of default | firewall-cmd --list-all

By OK -
Redhat recommends us to add  _netdev  option for NFS file system in /etc/fstab. So that they can be mounted after starting the networking service. Alternative ways to refer to partitions: Label : LABEL=label Network ID Samba : //server/share NFS : server:/share SSHFS : sshfs#user@server:/share Device : /dev/sdxy (not recommended) Example #1 //192.168.1.134/share_name /mnt/share_name cifs username=server_user,password=server_password,_netdev 0 0 ^ Path to your share ^ Mountpoint ^ Username ^ Password ^ See note A Note A: The  _netdev  options makes sure the mount is only attempted AFTER a network connection has been established. Example #2 10.10.10.1:/vol1/fs1 /data nfs defaults,_netdev 0 0 ============================ [root@localhost ~]# firewall-cmd --list-all public   target: default   icmp-block-inversion: no   interfaces:   sources:   services: dhcpv6-client high-availabi...
Read more