Tag: ssh

Cloud Services | Exadata | Linux, Linux, Shell Scripts

Amazon EC2: X11 Forwarding After Sudo SSH Session

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Hello all!

So, now with more use of resources like Cloud servers, more and more silent instalations are being done, right? Myself, I do it in silent always I can.

What if I need to export X. Plus, if I need to export it from user oracle, but I can only login with ec2-user, as usual?

Here is the process for that:

1) Connect to AWS EC2 instance

[user@securehost ~]$ ssh -X ec2-user@ipaddress
Last login: Fri Dec 7 14:41:41 2018 from grepora.srv.com
__| __|_ )
 _| ( / Amazon Linux AMI
 ___|\___|___|
https://aws.amazon.com/amazon-linux-ami/2018.03-release-notes/
13 package(s) needed for security, out of 16 available
Run "sudo yum update" to apply all updates.

2) Test xclock works from ec2-user

[ec2-user@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C

3) Show all magic cookie

[ec2-user@ipaddress ~]$ xauth list
ipaddress/unix:12 MIT-MAGIC-COOKIE-1 7e53e7600ff4177d7bbc66bde0a1b1ca
ipaddress/unix:11 MIT-MAGIC-COOKIE-1 e3d1a8915484c929ef3e809b047e6352
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

4) Show DISPLAY variable

[ec2-user@ipaddress ~]$ env|grep DISPLAY
DISPLAY=localhost:10.0

5) Create /tmp/xauth based on current DISPLAY variable

[ec2-user@ipaddress ~]$ xauth list | grep unix`echo $DISPLAY | cut -c10-12` > /tmp/xauth
[ec2-user@ipaddress ~]$ ll /tmp/xauth ; cat /tmp/xauth 
-rw-rw-r-- 1 ec2-user ec2-user 78 Dec 7 14:47 /tmp/xauth
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

6) Sudo to oracle

[ec2-user@ipaddress ~]$ sudo su - oracle
Last login: Fri Dec 7 14:43:12 UTC 2018 on pts/0

7) Add and Verify xauth

[oracle@ipaddress ~]$ xauth add `cat /tmp/xauth`
[oracle@ipaddress ~]$ xauth list
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

8) Verify and Add DISPLAY variable

[oracle@ipaddress ~]$ env|grep DISPLAY
[oracle@ipaddress ~]$ export DISPLAY=localhost:10.0

9) Test xclock works from oracle

[oracle@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C
[oracle@ipaddress ~]$

Now you should be able to see the clock and so other graphical resources, like DBCA and so on.

Hope it helps!

Linux

RHEL: Adding User/Group to SSH and SUDOERS file

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Some Linux basics… To add a group or a user (this case “new_group”) to the ssh and sudoers file:

[root@db-server ~]# vi /etc/ssh/sshd_config
[root@db-server ~]# cat /etc/ssh/sshd_config |grep new_group
AllowGroups ssh_group1 root oinstall linux new_group
[root@db-server ~]# vi /etc/sudoers
[root@db-server ~]# cat /etc/sudoers |grep new_group
%new_group      ALL=(ALL)       PASSWD: ALL
[root@db-server ~]# service sshd restart
Stopping sshd:                                             [  OK  ]
Starting sshd:                                             [  OK  ]
[root@db-server ~]#

Matheus.