Extend / Reduce SWAP Partitions in Linux

Extend Swap Partition.

1) Determine the name of the swap logical volume using the "lvs" command:

root@ubuntu:~# lvs
  LV       VG   Attr      LSize  Pool Origin Data%  Move Log Copy%  Convert
  motadata vg0  -wi-ao--- 71.52g
  root     vg0  -wi-ao--- 14.30g
  swap     vg0  -wi-ao---  7.63g

2) Turn off the swap partition:

root@ubuntu:~# swapoff /dev/mapper/vg0-swap

3) Resize the swap partition, adding 15GB more space to it:

root@ubuntu:~# lvresize -L +5G /dev/mapper/vg0-swap
  Extending logical volume swap to 12.63 GiB
  Logical volume swap successfully resized

4) Format the new swap space to make it usable:

root@ubuntu:~# mkswap /dev/mapper/vg0-swap
mkswap: /dev/mapper/vg0-swap: warning: don't erase bootbits sectors
on whole disk. Use -f to force.
Setting up swapspace version 1, size = 13242364 KiB
no label, UUID=a1ea414e-f650-4d11-8525-43ff01ed48d8

5) Turn the swap volume back on:

root@ubuntu:~# swapon /dev/mapper/vg0-swap




6) Use the free command to show your new swap space:

root@ubuntu:~# free -mh | grep -i swap
Swap: 12G 0B 12G

Configure DNS in Linux

- DNS = Domain Naming Service (or) Domain Name System DNS will resolve the host name for the particular IP address.
- WINS provides only netbios to IP but not from IP to netbios
- DNS & WINS reduces the broadcast
- Host file located in /etc/hosts

=> Zone
  - Storage database which contains all the records.
  1. Forward lookup Zone
      - Used for resolving hostnames to IP
      - Maintains host to IP mapping info
  2. Revers lookup Zone
      - Used to resolve IP to hostname
      - Maintains IP to host mapping info

=> Records
  1. PTR Record                                             /Reverse lookup Zone
      - Maps IP to Hostname
  2. SOA Record                                             /Forward lookup Zone
      - First Record in any zone file
      - Primary and Start Of Authority
  3. NS Record                                               /Forward lookup Zone
      - Name server
      - Identifies the DNS servers for each zone
  4. MX Record                                              /Forward lookup Zone
      - Maps domain name to a mail server
      - Mail Exchange
  5. A Record (Address Record)                      /Forward lookup Zone   
      - Maps hostname to an IP address
      - Client Side
  6. SRV Record                                             /Forward lookup Zone
      - Service Record
  7. CNAME Record (Canonical Name)
      - Maps an alias name to a hostname

=> Packages
   - bind*
   - caching-nameserver-*.rpm

=> Port number
   - 53

=> Configuration file
   - /etc/named.caching-nameserve.conf
   - /etc/named.rtc1912.zones

=> Daemon/Service
   - named

Primary(Master) DNS Server Details:

Operating System     : CentOS 6.5 server
Hostname             : masterdns.rhce.local 

IP Address       : 192.168.1.100/24[Installation on Server Side]

Secondary(Slave) DNS Server Details:

Operating System     : CentOS 6.5 server
Hostname             : secondarydns.rhce.local
IP Address           : 192.168.1.101/24

Client Details:

Operating System     : CentOS 6.5 Desktop  
Hostname             : Client.rhce.local
IP Address           : 192.168.1.102/24

Setup Primary(Master) DNS Server

[root@masterdns ~]# yum install bind* -y

1. Configure DNS Server

Add the lines as shown below in ‘/etc/named.conf’ file

[root@master ~]# vi /etc/named.conf 
//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
options {
listen-on port 53 { 127.0.0.1; 192.168.1.100; }; ### Master DNS IP ###
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
allow-query     { localhost; 192.168.1.0/24; }; ### IP Range ### 
allow-transfer{ localhost; 192.168.1.101; };   ### Slave DNS IP ###
recursion yes;
dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
};
logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};
zone "." IN {
type hint;
file "named.ca";
};
zone"rhce.local" IN {
type master;
file "forward.rhce";
allow-update { none; };
};
zone"1.168.192.in-addr.arpa" IN {
type master;
file "reverse.rhce";
allow-update { none; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

2. Create Zone files

Create forward and reverse zone files which we mentioned in the ‘/etc/named.conf’ file.

2.1 Create Forward Zone

Create forward.rhce file in the ‘/var/named’ directory.

[root@master ~]# vi /var/named/forward.rhce
$TTL 86400
@   IN  SOA     master.rhce.local. root.rhce.local. (
        2011071001  ;Serial
        3600        ;Refresh
        1800        ;Retry
        604800      ;Expire
        86400       ;Minimum TTL
)
@       IN  NS          master.rhce.local.
@       IN  NS          secondary.rhce.local.
@       IN  A           192.168.1.100
@       IN  A           192.168.1.101
@       IN  A           192.168.1.102
master       IN  A   192.168.1.100
secondary    IN  A   192.168.1.101
client          IN  A   192.168.1.102

2.2 Create Reverse Zone

Create reverse.rhce file in the ‘/var/named’ directory.

[root@master ~]# vi /var/named/reverse.rhce

$TTL 86400
@   IN  SOA     master.rhce.local. root.rhce.local. (
        2011071001  ;Serial
        3600        ;Refresh
        1800        ;Retry
        604800      ;Expire
        86400       ;Minimum TTL
)
@       IN  NS          master.rhce.local.
@       IN  NS          secondary.rhce.local.
@       IN  PTR         rhce.local.
master       IN  A   192.168.1.100
secondary    IN  A   192.168.1.101
client          IN  A   192.168.1.102
100     IN  PTR         master.rhce.local.
101     IN  PTR         secondary.rhce.local.
102     IN  PTR         client.rhce.local.

3. Start the DNS service

[root@master ~]# service named start
Starting named:                                            [  OK  ]
[root@master ~]# chkconfig named on

4. Adjust iptables to allow DNS server from outside of the network

Add the lines as shown below in ‘/etc/sysconfig/iptables’ file.

[root@master ~]# vi /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p udp -m state --state NEW --dport 53 -j ACCEPT
-A INPUT -p tcp -m state --state NEW --dport 53 -j ACCEPT
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

5. Restart iptables

[root@master ~]# service iptables restart
iptables: Flushing firewall rules:                         [  OK  ]
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Unloading modules:                               [  OK  ]
iptables: Applying firewall rules:                         [  OK  ]

6. Test DNS configuration and zone files for any syntax errors

[root@master ~]# named-checkconf /etc/named.conf 
[root@master ~]# named-checkzone rhce.local /var/named/forward.rhce 
zone rhce.local/IN: loaded serial 2011071001
OK
[root@master ~]# named-checkzone rhce.local /var/named/reverse.rhce
zone rhce.local/IN: loaded serial 2011071001
OK

7. Test DNS Server

[root@master ~]# dig master.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> master.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49834
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; QUESTION SECTION:
;master.rhce.local.INA
;; ANSWER SECTION:
master.rhce.local. 86400INA192.168.1.100
;; AUTHORITY SECTION:
rhce.local.86400INNSsecondary.rhce.local.
rhce.local.86400INNSmaster.rhce.local.
;; ADDITIONAL SECTION:
secondary.rhce.local. 86400 INA192.168.1.101
;; Query time: 6 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:07:56 2013
;; MSG SIZE  rcvd: 114

[root@master ~]# nslookup rhce.local
Server:192.168.1.100
Address:192.168.1.100#53
Name:rhce.local
Address: 192.168.1.102
Name:rhce.local
Address: 192.168.1.100
Name:rhce.local
Address: 192.168.1.101

Now the Primary DNS server is ready to use.

Setup Secondary(Slave) DNS Server

[root@secondary ~]# yum install bind* -y

1. Configure Slave DNS Server

Open the main configuration file ‘/etc/named.conf’ and add the lines as shown below.

[root@secondary ~]# vi /etc/named.conf 
//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
options {
listen-on port 53 { 127.0.0.1; 192.168.1.101; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
allow-query     { localhost; 192.168.1.0/24; };
recursion yes;
dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
};
logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};
zone "." IN {
type hint;
file "named.ca";
};
zone"rhce.local" IN {
type slave;
file "slaves/rhce.fwd";
masters { 192.168.1.100; };
};
zone"1.168.192.in-addr.arpa" IN {
type slave;
file "slaves/rhce.rev";
masters { 192.168.1.100; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

2. Start the DNS Service

[root@secondary ~]# service named start
Generating /etc/rndc.key:                                  [  OK  ]
Starting named:                                            [  OK  ]
[root@secondary ~]# chkconfig named on

Now the forward and reverse zones are automatically replicated from Master DNS server to ‘/var/named/slaves/’ in Secondary DNS server.

[root@secondary ~]# ls /var/named/slaves/
rhce.fwd  rhce.rev

[root@secondary ~]# cat /var/named/slaves/rhce.fwd 
$ORIGIN .
$TTL 86400; 1 day
rhce.localIN SOAmasterdns.rhce.local. root.rhce.local. (
2011071001 ; serial
3600       ; refresh (1 hour)
1800       ; retry (30 minutes)
604800     ; expire (1 week)
86400      ; minimum (1 day)
)
NS master.rhce.local.
NS secondary.rhce.local.
A192.168.1.100
A192.168.1.101
A192.168.1.102
$ORIGIN rhce.local.
clientA192.168.1.102
masterA192.168.1.100
secondaryA192.168.1.101

[root@secondary ~]# cat /var/named/slaves/rhce.rev 
$ORIGIN .
$TTL 86400; 1 day
1.168.192.in-addr.arpaIN SOAmaster.rhce.local. root.rhce.local. (
2011071001 ; serial
3600       ; refresh (1 hour)
1800       ; retry (30 minutes)
604800     ; expire (1 week)
86400      ; minimum (1 day)
)
NS master.rhce.local.
NS secondary.rhce.local.
PTRrhce.local.
$ORIGIN 1.168.192.in-addr.arpa.
100PTRmaster.rhce.local.
101PTRsecondary.rhce.local.
102PTRclient.rhce.local.
clientA192.168.1.102
masterA192.168.1.100
secondaryA192.168.1.101

3. Add the DNS Server details to all systems

[root@secondary ~]# vi /etc/resolv.conf
# Generated by NetworkManager
search rhce.com
nameserver 192.168.1.100
nameserver 192.168.1.101
nameserver 8.8.8.8

4. Test DNS Server

[root@secondary ~]# dig masterdns.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> master.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21487
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; QUESTION SECTION:
;master.rhce.local.INA
;; ANSWER SECTION:
master.rhce.local. 86400INA192.168.1.100
;; AUTHORITY SECTION:
rhce.local.86400INNSmaster.rhce.local.
rhce.local.86400INNSsecondary.rhce.local.
;; ADDITIONAL SECTION:
secondary.rhce.local. 86400 INA192.168.1.101
;; Query time: 15 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:27:57 2013
;; MSG SIZE  rcvd: 114

[root@secondary ~]# dig secondary.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.6 <<>> secondary.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20958
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; QUESTION SECTION:
;secondary.rhce.local.INA
;; ANSWER SECTION:
secondary.rhce.local. 86400 INA192.168.1.101
;; AUTHORITY SECTION:
rhce.local.86400INNSmaster.rhce.local.
rhce.local.86400INNSsecondary.rhce.local.
;; ADDITIONAL SECTION:
master.rhce.local. 86400INA192.168.1.100
;; Query time: 4 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:31:53 2013
;; MSG SIZE  rcvd: 114

[root@secondary ~]# nslookup rhce.local
Server:192.168.1.100
Address:192.168.1.100#53
Name:rhce.local
Address: 192.168.1.101
Name:rhce.local
Address: 192.168.1.102
Name:rhce.local
Address: 192.168.1.100

Client Side Configuration

Add the DNS server details in ‘/etc/resolv.conf’ file in all client systems

[root@client rhce]# vi /etc/resolv.conf
# Generated by NetworkManager
search rhce.local
nameserver 192.168.1.100
nameserver 192.168.1.101
nameserver 8.8.8.8

Test DNS Server

[root@client rhce]# dig master.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6 <<>> master.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19496
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; QUESTION SECTION:
;master.rhce.local.INA
;; ANSWER SECTION:
master.rhce.local. 86400INA192.168.1.100
;; AUTHORITY SECTION:
rhce.local.86400INNSmaster.rhce.local.
rhce.local.86400INNSsecondary.rhce.local.
;; ADDITIONAL SECTION:
secondary.rhce.local. 86400 INA192.168.1.101
;; Query time: 30 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:47:55 2013
;; MSG SIZE  rcvd: 114

[root@client rhce]# dig secondary.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6 <<>> secondary.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14852
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; QUESTION SECTION:
;secondary.rhce.local.INA
;; ANSWER SECTION:
secondary.rhce.local. 86400 INA192.168.1.101
;; AUTHORITY SECTION:
rhce.local.86400INNSsecondary.rhce.local.
rhce.local.86400INNSmaster.rhce.local.
;; ADDITIONAL SECTION:
master.rhce.local. 86400INA192.168.1.100
;; Query time: 8 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:48:38 2013
;; MSG SIZE  rcvd: 114

[root@client rhce]# dig client.rhce.local
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6 <<>> client.rhce.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14604
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;client.rhce.local.INA
;; ANSWER SECTION:
client.rhce.local.86400INA192.168.1.102
;; AUTHORITY SECTION:
rhce.local.86400INNSmaster.rhce.local.
rhce.local.86400INNSsecondary.rhce.local.
;; ADDITIONAL SECTION:
master.rhce.local. 86400INA192.168.1.100
secondary.rhce.local. 86400 INA192.168.1.101
;; Query time: 5 msec
;; SERVER: 192.168.1.100#53(192.168.1.100)
;; WHEN: Thu Mar  7 13:49:11 2013
;; MSG SIZE  rcvd: 137

[root@client rhce]# nslookup rhce.local
Server:192.168.1.100
Address:192.168.1.100#53
Name:rhce.local
Address: 192.168.1.102
Name:rhce.local
Address: 192.168.1.100
Name:rhce.local
Address: 192.168.1.101

Now the primary and secondary DNS servers are ready to use.

Create and configure DHCP in Linux

DHCP works on D.O.R.A(Discover, Offer, Request, Acknowledge) process.

F.Q.D.N = Hostname + Domain Name

=> 67 port number for Server
    68 port number for Client

=> Set the hostname
  - # hostname <hostname> (But this is temporary)

=> Set Hostname permanent
  - # vim /etc/sysconfig/network
       Networking=Yes
       hostname <hostname>

=> By default the DHCP lease duration for wired Network is 6Days & for Wireless it is 7Hours.
=> To assign IP address 
  - # setup OR # netconfig
  - # service network restart  (to make the changes)
  - # ifconfig (to check the IP address)

=> Installation Packages.
  - dhcp*

=> Configuration File.
  - /etc/dhcpd.conf

=> Daemon/Service
  - dhcpd

=> Sample file of DHCP to copy it to the main configuration file.
  - /usr/share/doc-dhcp-<version>/dhcp.conf.sample

=> DHCP lease database file.
  - /var/lib/dhcpd/dhcpd.lease

Installation of DHCP Sever

# rpm -qa | grep dhcp (To check if it is already installed or not)
# yum install dhcp*
# cp /usr/share/doc-dhcp-<version>/dhcp.conf.sample /etc/dhcpd.conf
# gedit /etc/dhcpd.conf
Option routers 192.168.0.254   -/ Gateway
(Put # at NIS-Domain)
Domain name-server 192.168.0.254
range dynamic bootp 192.168.0.100 192.168.0.150
lease time 2
(save the file)
# service dhcpd restart
# service dhcpd status
# chkconfig dhcpd on
# chkconfig --list dhcpd
# netstat -ntpul | grep :67 (To show port status)

Now verify it from the client side.

Configure rsync to sync data between two Linux/Unix server (Backup data)

What is Rsync

Rsync (Remote Sync) is a  most commonly used command for copying and synchronizing files and directories remotely as well as locally in Linux/Unix Systems,

With the help of rsync command you can copy and synchronize your data remotely and locally across directories, across disks and networks, perform data backups and mirroring between two Linux machines.

Advantages and features of rsync command

1. It efficiently copies and sync files to or from a remote system.
2. Supports copying links, devices, owners, groups and permissions.
3. It’s faster than scp (Secure Copy) because rsync uses remote-update protocol which allows to transfer just the differences between two sets of files. First time, it copies the whole content of a file or a directory from source to destination but from next time, it copies only the changed blocks and bytes to the destination.
4. Rsync consumes less bandwidth as it uses compression and decompression method while sending and receiving data both ends.

syntax of rsync command

# rsync options source destination

common options used with rsync commands

1. -v : verbose
2. -r : copies data recursively (but don’t preserve timestamps and permission while transferring data
3. -a : archive mode, archive mode allows copying files recursively and it also preserves symbolic links, file permissions, user & group ownerships and timestamps
4. -z : compress file data
5. -h : human-readable, output numbers in a human-readable format

1. Copy/Sync Files and Directory Locally

[root@gcdc-nms source]# rsync -azvh /opt/source/ /tmp/backup/

sending incremental file list

created directory /tmp/backup

./

1

2

3

4

file1

sent 255 bytes  received 110 bytes  730.00 bytes/sec

total size is 0  speedup is 0.00

[root@gcdc-nms source]#

2. Copy/Sync Files and Directory to or From a Remote Server

[root@gcdc-nms source]# rsync -azvh /opt/source/ root@10.200.236.60:/tmp/backup/

root@10.200.236.60's password:

sending incremental file list

created directory /tmp/backup

./

1

2

3

4

file1

sent 255 bytes  received 110 bytes  42.94 bytes/sec

total size is 0  speedup is 0.00

You have new mail in /var/spool/mail/root

[root@gcdc-nms source]#

3. Rsync Over SSH

[root@gcdc-nms source]# rsync -azvhP -e ssh /opt/source/ root@10.200.236.60:/tmp/backup
/root@10.200.236.60's password:sending incremental file listcreated directory /tmp/backup./1           0 100%    0.00kB/s    0:00:00 (xfer#1, to-check=4/6)2           0 100%    0.00kB/s    0:00:00 (xfer#2, to-check=3/6)3           0 100%    0.00kB/s    0:00:00 (xfer#3, to-check=2/6)4           0 100%    0.00kB/s    0:00:00 (xfer#4, to-check=1/6)file1           0 100%    0.00kB/s    0:00:00 (xfer#5, to-check=0/6)sent 255 bytes  received 110 bytes  42.94 bytes/sectotal size is 0  speedup is 0.00
[root@gcdc-nms source]#

4. Use of –include and –exclude Options

[root@gcdc-nms source]# ll

total 0

-rw-r--r-- 1 root root 0 Apr 19 09:58 file1.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file2.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file3.log

[root@gcdc-nms source]# rsync -azvP --include '*.txt' --exclude '*' -e ssh /opt/source/ root@10.200.236.60:/tmp/backup/

root@10.200.236.60's password:

sending incremental file list

created directory /tmp/backup

./

file1.txt

           0 100%    0.00kB/s    0:00:00 (xfer#1, to-check=1/3)

file2.txt

           0 100%    0.00kB/s    0:00:00 (xfer#2, to-check=0/3)

sent 130 bytes  received 53 bytes  21.53 bytes/sec

total size is 0  speedup is 0.00

[root@gcdc-nms source]#

5. Use of –delete Option

[root@gcdc-nms source]# ll

total 0

-rw-r--r-- 1 root root 0 Apr 19 09:58 file1.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file2.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file3.log

[root@gcdc-nms source]# ll ../destination/

total 0

-rw-r--r-- 1 root root 0 Apr 18 13:01 file1

[root@gcdc-nms source]# rsync -azvP --delete -e ssh /opt/source/ root@10.200.236.60:/opt/destination/

root@10.200.236.60's password:

sending incremental file list

./

deleting file1

file1.txt

           0 100%    0.00kB/s    0:00:00 (xfer#1, to-check=2/4)

file2.txt

           0 100%    0.00kB/s    0:00:00 (xfer#2, to-check=1/4)

file3.log

           0 100%    0.00kB/s    0:00:00 (xfer#3, to-check=0/4)

sent 181 bytes  received 72 bytes  29.76 bytes/sec

total size is 0  speedup is 0.00

You have new mail in /var/spool/mail/root

[root@gcdc-nms source]# ll ../destination/

total 0

-rw-r--r-- 1 root root 0 Apr 19 09:58 file1.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file2.txt

-rw-r--r-- 1 root root 0 Apr 19 09:58 file3.log

[root@gcdc-nms source]#

6. Setup cron job for rsync

Generate the rsa file on client side (Destination). 

[root@gcdc-nms opt]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): /root/.ssh/rsync_key
Enter passphrase (empty for no passphrase): [Hit Enter]
Enter same passphrase again: [Hit Enter]
Your identification has been saved in /root/.ssh/rsync_key.
Your public key has been saved in /root/.ssh/rsync_key.pub.
The key fingerprint is:
SHA256:9hAlaN2gBCOmbIVv4QcGOiMSZp9yIHcVFgeWvHizo/4 root@gcdc-nms.localdomain
The key's randomart image is:
+---[RSA 2048]----+
|o=*.++OB+o.      |
|**+*.==o.o.      |
|B+++oo...        |
|+oo+..+  .       |
|  . .. oS        |
|      o. o       |
|     . .  .      |
|    .            |
|   ...E          |
+----[SHA256]-----+

Now copy the key to server (Source) from Client (destination).

[root@gcdc-nms ~]# cat /root/.ssh/rsync_key.pub | ssh root@10.200.236.60 "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >>  ~/.ssh/authorized_keys"

[root@gcdc-nms ~]# cp /root/.ssh/rsync_key /opt/rsa/

[root@gcdc-nms ~]# ls /opt/rsa/

key  key.pub  rsync_key

[root@gcdc-nms ~]# 

Now check rsync on server (source)

[root@gcdc-nms ~]# rsync -azvP --delete -e "ssh -i /opt/rsa/rsync_key" /opt/source/ root@10.200.236.60:/opt/destination/              sending incremental file list

sent 63 bytes  received 12 bytes  13.64 bytes/sec

total size is 0  speedup is 0.00

You have new mail in /var/spool/mail/root

[root@gcdc-nms ~]#

Setup a cron job

First create a script which contains the rsync commands.

[root@gcdc-nms ~]# vim /opt/backup

rsync -azvP --delete -e "ssh -i /opt/rsa/rsync_key" /opt/source/ root@10.200.236.60:/opt/destination/

[root@gcdc-nms ~]# chmod 775 /opt/backup

Now create a cron job.

[root@gcdc-nms ~]# crontab -e

* * * * * sh /opt/backup

[Solved] Unable To Import OVA due to ISO mounted VM exported

1.  Uncompress the OVA file to local drive.

      

      2. Open the OVF file (i.e.: gc2nfe-clone.ovf) in notepad. This file contains all the configuration information to deploy the virtual machine.

      

 3. In the gc2nfe-clone.ovf file, Search for “vmware.cdrom.iso” and replace it with “vmware.cdrom.remotepassthrough”.

                    

4.       Save the gc2nfe-clone.ovf file.

5.       Now move the .mf file to any other location.

        

       6.       Now import vm as OVF.