cPanel : sshd has failed, please contact the sysadmin

If you have changed the shell default Port 22 on a cPanel powered server , restarting sshd from the WHM will fail. You have to ssh to the server and issue the following command to restart sshd…


  • /sbin/service sshd restart

To, temporarily, reset your shell port back to 22, run the following command from the Address field in browser:

    SERVER_MAIN_IP:2087/scripts2/doautofixer?autofix=safesshrestart

Now, you should be able to access shell, and you need to restart sshd at the prompt using the command mentioned above



Formatting and Mounting a new drive in Linux

I have installed a new slave hard drive. How do I format it and mount it?

Solution:

1. Login as root: and type the following command:

[root@34 root]# fdisk /dev/hdc

2. This screen will appear:

The number of cylinders for this disk is set to 10011.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)

3. Press p for print, this will show you the current partitons on the drive:

Command (m for help): p

Disk /dev/hdc: 82.3 GB, 82348277760 bytes
255 heads, 63 sectors/track, 10011 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

4. There are no current partitions, if there were, press d to delete them. Then press n to create a new partition and follow the rest of the commands:

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-10011, default 1): Enter
Using default value 1: Enter
Last cylinder or +size or +sizeM or +sizeK (1-10011, default 10011): Enter
Using default value 10011

5: Write your new partiton to the drive:

Command (m for help): w
The partition table has been altered!

—————————————

6. Now to make the file system.

[root@34 root]# mkfs.ext3 /dev/hdc1
mke2fs 1.32 (09-Nov-2002)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
10059776 inodes, 20103331 blocks
1005166 blocks (5.00%) reserved for the super user
First data block=0
614 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424

—————————————–

7. Now to make a directory to mount the new drive to.

[root@34 root]# mkdir /backups
[root@34 root]# mount /dev/hdc1 /backups
[root@34 root]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 75G 1.3G 70G 2% /
/dev/hda1 99M 14M 81M 15% /boot
none 243M 0 243M 0% /dev/shm
/dev/hdc1 76G 33M 72G 1% /backups

You will see that the new drive is labled /dev/hdc1 and is mounted to /backups.
——————————————-

8. Now edit the /etc/fstab so that the mount is there after a reboot.

Current fstab is shown below:

LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
none /dev/pts devpts gid=5,mode=620 0 0
none /proc proc defaults 0 0
none /dev/shm tmpfs defaults 0 0
/dev/hda2 swap swap defaults 0 0

9. Now we are going to add one line at the end:

[root@34 root]# vi /etc/fstab
LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
none /dev/pts devpts gid=5,mode=620 0 0
none /proc proc defaults 0 0
none /dev/shm tmpfs defaults 0 0
/dev/hda2 swap swap defaults 0 0
/dev/hdc1 /backups ext3 defaults 0 0

Save and quit vi.

rndc: the key is invalid

Problem:

———
Issue:
———
While starting named, or when running /etc/rc.d/init.d/named status, you get the following error:
rndc: connection to remote host closed This may indicate that the remote server is using an older version of the command protocol, this host is not authorized to connect, or the key is invalid.


Solution:

——-
Fix:
——-

Run rndc-confgen.
running rndc-confgen would ouput something like this:
# Start of rndc.conf
key “rndc-key” {
algorithm hmac-md5;
secret “lYzcmf255w8BC6PHTSYCQA==”;
};

options {
default-key “rndc-key”;
default-server 127.0.0.1;
default-port 953;
};
# End of rndc.conf

# Use with the following in named.conf, adjusting the allow list as needed:
# key “rndc-key” {
# algorithm hmac-md5;
# secret “lYzcmf255w8BC6PHTSYCQA==”;
# };
#
# controls {
# inet 127.0.0.1 port 953
# allow { 127.0.0.1; } keys { “rndc-key”; };
# };
# End of named.conf

do as mentioned in the output, that is, copy the rndc.conf part to /etc/rndc.conf (of course, remove all the existing entries)
in /etc/named.conf, remove the existing key and controls section, and paste the one from the output of rndc-confgen.
restart named (/etc/rc.d/init.d/named restart).
This fixes the issue

semget: No space left on device

This relates to semaphores on your system (you’ve run out). Run the following to clear them out:

ipcs | grep apache | awk ‘{print $2}’ > sem.txt
for i in `cat sem.txt`; do { ipcrm -s $i; }; done;

For cPanel servers :

ipcs | grep nobody | awk ‘{print $2}’ > sem.txt
for i in `cat sem.txt`; do { ipcrm -s $i; }; done;

 

Finally restart Apache :

/etc/init.d/httpd restart

Or 
service httpd restart