Restore Windows Server VM from Recovery mode

How to Restore Windows Server VM from Recovery mode.

1. Insert your Windows Server installation disc and restart your VM and Boot from CD through Console.

2. Choose your language settings, and click “Next.”

3. Click “Repair your computer.”

4. Go to Command Promt. And type following command.

Bootrec /fixmbr

Bootrec /fixboot

BCD Boot C:\Windows

Bootrec /rebuildbcd

Bootsect /nt60 all /force

5. Now restart your Vm and select Last Known Good Configuration or you can also select Start Windows normally.

If you start VM and it gives following error or any registry file missing error.

File: \Windows\system32\config\system

Status: 0xc000014c

Info: Windows failed to load because the system registry file is missing, or corrupt.

Do follow these steps.

6. Do steps 1 to 4 above.
7. Type: cd c:\Windows\system32\config
8. Type: ren SYSTEM SYSTEM.BACKUP
9. Type: copy regback\SYSTEM SYSTEM
10. Reboot your machine and it should boot normally.

It should start good now. Cheers (Y)

How to create FTP server in CentOS

Recently I have deployed a couple of FTP servers both at work and one in home to create a central point for all my data especially in home and also separate for one of our clients at work.

Although creating an FTP server is an easy workaround but just to sum up and provide few details on small security issues and are which can be tuned.
Installs nano (editor) and vsftpd (Very Secure FTP) repo
yum install nano vsftpd -y

This step was required as we were having trouble with client unable to create folders etc on FTP server (Although it was a strange issue but writing it down to make sure that if someone faces "ftp error 550 failed to create directory" then this might work
nano /etc/selinux/config

SELINUX=enforcing ----> SELINUX=permissive

reboot

Start vsftpd services
/etc/init.d/vsftpd start

Open the configuration file of vsftpd and then make sure that following lines match
nano /etc/vsftpd/vsftpd.conf
anonymous_enable=NO
local_enable=YES
write_enable=YES
local_umask=022
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_std_format=YES
ascii_upload_enable=YES
ascii_download_enable=YES
ftpd_banner=Welcome to AMMAR FTP service.
chroot_local_user=YES
listen=YES
pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES (if this is enabled then FTP will read (/etc/hosts.allow) to secure server acess
use_localtime=yes

Restart vsftpd services
service vsftpd restart


setsebool -P ftp_home_dir on

Stop iptables as it block ftp port by default although this is not a good practice later on I will update it to allow FTP port in iptables
service iptables stop

Add a user to be used in ftp (we can also include a file create a users list) currently I have worked using this method but there are other ways also
useradd client

Enter Client password
passwd client

User is normally able to access the server via SSH as we want only user to connect via FTP then:
chsh -s /sbin/nologin client (where client is username)

Create Directory for mounting drive locally or via NFS
mkdir /home/client/data

To add Drive via NFS following repo are required 
yum install nfs-utils nfs-utils-lib -y

Add below line to add the NFS chunk on to FTP server
nano /etc/fstab
172.19.30.16:/failover/clientdata  /home/client/data nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0

To mount the NFS following command will be used, if the first command doesn't work then second or third command will work depending upon your configuration

mount 172.19.30.16:/failover/clientdata /home/client/data/
mount -o 172.19.30.16:/failover/clientdata /home/client/data/

mount -o nolock 172.19.30.16:/failover/clientdata /home/client/data/

Execute this command to see the mounted drive
df -h

Give permission and rights to the user on the folder
chown -R client /home/client/data
usermod -d /home/client/data/ client

Restart vsftpd services
service vsftpd restart

Stop iptables services or allow port via firewall rules

service iptables stop

To make sure services stop or start after reboot
chkconfig vsftpd on
chkconfig iptables off

How to access System VMs in Cloudstack

Recently I have been working in managing Cloudstack at my work.  Cloudstack uses 3 types of system VMs for its operation.
1. SSVM - Secondary storage VM: This VM basically mounts the secondary storage which is used for templates, snapshots, ISO for cloudstack.
2. CP - Console Proxy VM: This VM is used basically to view the console (Type of VNC View) of the machine as it is not a physical machine and for access off VM if network is unreachable.
3. VR - Virtual Router:This VM is generated when any account user creates a VM and every VM requires a network, which secures network of that account and access to VMs of that particular user. It also provides DHCP services to make that VM traffic reach the WWW and vice verse.

We continuously require access to these VM mostly VR and SSVM for different debugging (will be updating blog about cloudstack extensively) and for operations.

To access these VMs we need to access the Host they are in which we can find from VMs details

we can find the details of host as well as the link local IP from which we can access without the need of password by going in infrastructure -> System VM or Virtual Router and details will be displayed as above. 

Simply access the host in which VM is and run following command:

ssh -i /root/.ssh/id_rsa.cloud -p 3922 root@169.254.x.x

Where x.x refers to IP which changes from time to time but first two octets are same always.!

After running the above command it will not ask for any username and password and VM can be accessed through this command.

(Hope it Helps !)

initramfs ubuntu boot problem

Recently one of our server crashed which was running Ubuntu-x64. On display it was showing below errors.

Then I booted the Machine using Ubuntu ISO and selected rescue mode.

After selecting rescue mode it prompted for simple options as we get during installation. In the end it prompts for selecting boot path. I selected then /ubuntu/root (this might be different according to your partitions.

Hope it works for you as well !

Error backup config files from Powerconnect 6248

Today we needed to perform module change in one of our Dell Powerconnect 6248 switch. From all the switches I was able to download configuration files but was getting error on one of our switch " Error while opening source file (temp-config.scr)" . I tried copying startup-config as well as backup-config but was getting error.

I did some googling but was unable to get anything. Then I copied the running config to backup config.

Switch1#copy running-config backup-config


This operation may take a few minutes.
Management interfaces will not be available during this time.

Are you sure you want to save? (y/n) y
Configuration Saved!

then I copied it to my tftp server it worked!.