Failed to start lsb bring up/down networking in rhel 7

Such type of error we have received after operating system upgradation from redhat linux operating system from version 7.x to version 7.y.

The root cause for error is network manager upgradation during operating system patching.

To troubleshoot this error, please restart the network service and check the status 

[root@localhost network-scripts]# systemctl restart network

Job for network.service failed because the control process exited with error code. See "systemctl status network.service" and "journalctl -xe" for details.

[root@localhost network-scripts]# systemctl status network

You can see " Failed to start lsb bring up/down networking" error message

Solution: To resolve such type of network issue, please perform the below steps.

Go to /etc/sysconfig/network-scripts/ directory and list the files.

[root@localhost]# cd /etc/sysconfig/network-scripts/

You can see the ifcfg-lo filename file which you need to removed it.

after remove this file please take a restart of service. Your network service will restart properly without any issue. Also if you have any other duplicate or backup ifcfg file please remove it.

[root@localhost network-scripts]# rm -rf ifcfg-lo

[root@localhost network-scripts]# systemctl restart network

Now try to access the redhat machine via ssh. Please post your comment if you have any query regarding this post. 

How to install and configure samba server in RHEL 7 or redhat linux 7

Login on Samaba server
Check samba rpm installed or not, if not installed please install it,

[root@localhost ~]# rpm -qa | grep samba
[root@localhost ~]# yum install samba*

Create a directory in root file system which is shared with client.

[root@localhost ~]#mkdir -p /home/testuser/test

Add a new group or can use existing group

To provide access on shared directory,Here we are adding new group called samba

[root@localhost ~]#groupadd samba

Change the group and permission of sharing folder

[root@localhost ~]#chgrp -R samba /home/testuser/test
[root@localhost ~]#chmod -R 777 /home/testuser/test

create user, add into group and set samba password

[root@localhost ~]#useradd testuser
[root@localhost ~]#usermod -G samba testuser
[root@localhost ~]#smbpasswd -a testuser

Now Edit /etc/samba/smb.conf file

Note: Please take a backup of origianl file.

[root@localhost ~]#cd /etc/samba/
[root@localhost ~]#cp -p smb.conf smb.conf.orig

And add the below given contents in last line of /etc/samba/smb.conf file.

vi /etc/samba/smb.conf

[test]
comment = shared-directory
path = /home/testuser/test
public = no
valid users = testuser, @samba
writable = yes
browseable = yes
create mask = 0774
directory mask = 4774

##Edit these lines in /etc/samba/smb.conf . To allow network to reach samba server

interfaces = lo ens32 192.168.1.0/24
hosts allow = 127. 192.168.1.

security = user
passdb backend = tdbsam
netbios name = localhost
server string = Samba Server localhost
workgroup = MYGROUP
log file = /var/log/samba/samba.log
max log size = 50
security = server

Add services in /etc/services files

vi /etc/services
 
netbios-ns    137/tcp    # netbios name service
netbios-ns    137/udp    # netbios name service
netbios-dgm    138/tcp    # netbios datagram service
netbios-dgm    138/udp    # netbios datagram service
netbios-ssn    139/tcp    # netbios session service
netbios-ssn    139/udp    # netbios session service

Note: Please check these above ports are open from this samba server to client machine

Now start the smb and nmb services.

systemctl start smb.service
systemctl start nmb.service

Enable smb and nmb service at booting of system

systemctl enable smb.service
systemctl enable nmb.service

Note 1: firewalld service not enable on this server so no need to add any rule.
Note 2: selinux is in permissive state so no need to change the selinux security context.

Now login on window machine

and mount this samba share on the server.

\\localhost.redhat.com\test

Job for nfs-server.service failed because the control process exited with error code. See "systemctl status nfs-server.service" and "journalctl -xe" for details. Resolution

On Red Hat Linux 7 operating system, some time you will get below NFS service failed error message.

"Job for nfs-server.service failed because the control process exited with error code. See "systemctl status nfs-server.service" and "journalctl -xe" for details."

The above error occur when you are taking restart of nfs service.

# systemctl restart nfs.service
Job for nfs-server.service failed because the control process exited with error code. See "systemctl status nfs-server.service" and "journalctl -xe" for details.
Resolution

# systemctl status nfs-server.service
nfs-server.service - NFS server and services
   Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2018-04-27 09:56:08 IST; 8s ago
  Process: 21370 ExecStopPost=/usr/sbin/exportfs -f (code=exited, status=0/SUCCESS)
  Process: 21366 ExecStopPost=/usr/sbin/exportfs -au (code=exited, status=0/SUCCESS)
  Process: 21362 ExecStop=/usr/sbin/rpc.nfsd 0 (code=exited, status=0/SUCCESS)
  Process: 21273 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
  Process: 2714 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=1/FAILURE)
 Main PID: 21273 (code=exited, status=0/SUCCESS)

Apr 27 09:56:07 localhost.redhat.com systemd[1]: Starting NFS server and services...
Apr 27 09:56:08 localhost.redhat.com exportfs[2714]: exportfs: Failed to resolve foobar.com <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Apr 27 09:56:08 localhost.redhat.com exportfs[2714]: exportfs: Failed to resolve foobar.com <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Apr 27 09:56:08 localhost.redhat.com systemd[1]: nfs-server.service: control process exited, code=exited status=1
Apr 27 09:56:08 localhost.redhat.com systemd[1]: Failed to start NFS server and services.
Apr 27 09:56:08 localhost.redhat.com systemd[1]: Unit nfs-server.service entered failed state.
Apr 27 09:56:08 localhost.redhat.com systemd[1]: nfs-server.service failed.

To resolve such issue you need to follow the below process.

You need to check which NFS version rpm is installed on the server.

#rpm -qa | grep nfs

the above command show you the installed nfs version.

Normally the above error occur due to lower version on nfs, so to resolve the issue you need to upgrade the nfs version.

installed the latest nfs rpm nfs-utils-1.3.0-0.33.el7 or later

#yum install nfs

The above command upgrade the nfs rpm, or you can download the manually rpm file and installed it through rpm -uvh command.

After that restart the nfs service again.

# systemctl restart nfs.service

it is started successfully, you can check the status via below command.

# systemctl status nfs.service

[root@localhost ~]# systemctl status nfs.service
● nfs-server.service - NFS server and services
   Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; disabled; vendor preset: disabled)
  Drop-In: /run/systemd/generator/nfs-server.service.d
           └─order-with-mounts.conf
   Active: active (exited) since Thu 2018-04-27 03:47:57 IST; 18h ago
  Process: 32477 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
  Process: 32472 ExecStartPre=/bin/sh -c /bin/kill -HUP `cat /run/gssproxy.pid` (code=exited, status=0/SUCCESS)
  Process: 32469 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
 Main PID: 32477 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/nfs-server.service

Apr 26 03:47:57 localhost systemd[1]: Starting NFS server and services...
Apr 26 03:47:57 localhost systemd[1]: Started NFS server and services.

How to start/stop and enable/disable Firewall on Redhat 7 Linux system

In RHEL7, to stop/start and enable/disable the firewall is quite different from RHEL6. In Red hat 7 "firewalld" named service we used for local firewall. Please find the below example step by step to check the firewall status.

How to check status of RHEL7 firewall:

[root@localhost ~]# systemctl status firewalld
firewalld.service - firewalld - dynamic firewall daemon

Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)

Active: active (running) since Thu 2018-02-05 12:37:47 IST; 0 months 1 days ago

Main PID: 332 (firewalld)

CGroup: /system.slice/firewalld.service
           └─332 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Feb 05 12:37:47 localhost systemd[1]: Starting firewalld - dynamic firewall daemon...
Feb 05 12:37:49 localhost systemd[1]: Started firewalld - dynamic firewall daemon.

In the above status firewall is by default enable on the linux system. It is enable automatically when system restart or on.

How to Stop and Start RHEL7 firewall:

 

Please use the below commands to start stop the firewall on redhat linux 7 operating system. 

[root@localhost ~]# service firewalld stop
Redirecting to /bin/systemctl stop  firewalld.service
Stopped firewall will start again after system's reboot.

[root@localhost ~]# service firewalld start
Redirecting to /bin/systemctl start  firewalld.service

How to Disable and Enable RHEL7 firewall:

If you want to disable permanently firewall so that after reboot it is not enable again, please use the below command.

[root@localhost ~]# systemctl disable firewalld
rm '/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service'
rm '/etc/systemd/system/basic.target.wants/firewalld.service'

If you want to enable the firewall again run please use the below command.

[root@localhost ~]# systemctl enable firewalld
ln -s '/usr/lib/systemd/system/firewalld.service' '/etc/systemd/system/basic.target.wants/firewalld.se