How to Fix Cannot open your terminal ‘/dev/pts/2’ – please check

by A. J.

Normally we see a common error when we switch or sudo to a user to run the screen session and it gets closes with the error ‘Cannot open your terminal ‘/dev/pts/2′ – please check’. fix it very tiny but it took a long for me to find so I thought I will share the quick fix and save our prices time.

Error:

[thedbadmin@testdb01 ~]$ screen -x 12991.screen_testCannot open your terminal ‘/dev/pts/0’ – please check.[thedbadmin@testdb01 ~]$

Step 1: logout from the user that you have logged in.

Step 2: log as your user or from where you want to run screen and just give full privileged to /dev/pts/*

Fix : 
$ chmod 777 /dev/pts/*

Note: if you get any warning or error after executing the above command, just ignore it safely.

Now you can start the screen again hopefully you won’t see that error again

Happy programming !!!

How to fix Rocky Linux full screen issue on Oracle Virtual Box

by A. J.

In this article, we will fix the rocky Linux full-screen issue on the oracle virtual box. Normally after installing rocky Linux on virtual box by default full scree don’t work and some times its annoying because it little hard to work with small screen. Let me give you few simple steps with commands which will fix this issue and you will many option to set screen resolution on rocky Linux.

Step 1: login as root and run following commands.

Commands:

yum install dkms gcc make kernel-devel bzip2 binutils patch libgomp glibc-headers glibc-devel kernel-headers -y

Important Note: In case if you don’t find the yum packages, configure epel yum repository for centos 8

Step 2: Install the virtual box guest addition. You can see the navigation from flowing screenshot

Step 3: restart your rocky Linux virtual machine

Command:

[root@rocky01 ~]# reboot

You are Done !!!

Read More

Take MySQL backup From Jenkins Job

How to fix ORA-28368: cannot auto-create wallet
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How to Manage AWS S3 Bucket with AWS CLI

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AWS MySQL RDS Database Creation using AWSCLI
How to Create MySQL Database with AWS RDS
How to connect to AWS MySQL / MariaDB RDS or EC2 database from MySQL WorkBench

MySQL query output to csv

by A. J.

There are situations when we have to run the select queries on MySQL databases and redirect the output in .cav format. This is required when we have to share the data with the developer or send it to some ETL job for external tables. In addition, if you are running MySQL on AWS RDS you get limited options to get the MySQL query output to CSV. As an alternative, you can use the AWS S3 bucket but again it’s a complex and cost-involved way of getting MySQL query output to CSV. I am going to show you an easy alternative that will work on a normal Linux command prompt. Using this you can fetch a long SQL output in CSV from MySQL RDS or from on promises MySQL Database instance.

Step 1: log in to any jump host or bastion host

ssh [email protected]

Step 2: if your SQL output is going to take a long time use screen

screen -S mysql2csv_date

Step 3 Run MySQL export batch command and sed Linux command

mysql -A -h testdb01.us-east-1.rds.amazonaws.com -u root -p --batch -e "select * from testdb01.table_x where date_created >='2021-07-01 00:00:00'  AND LENGTH(emp_id) < 30 order by date_created;" | sed 's/\t/","/g;s/^/"/;s/$/"/;s/\n//g' > mysq2csv_output.csv

Step 4: once the command is completed you will see the output in .csv under the file mysq2csv_output.csv

Hope you like the article

References: https://dev.mysql.com/doc/refman/8.0/en/select-into.html

Read More

Take MySQL backup From Jenkins Job

How to fix ORA-28368: cannot auto-create wallet
AWS Services and their Azure alternatives
How to Manage AWS S3 Bucket with AWS CLI

Take MySQL backup From Jenkins Job

by A. J.

Take MySQL Database Backup From Jenkins

In this post, we will explain and practically show how you can configure MySQL database backup using Jenkins jobs. in easy words, you will automate the MySQL database backup process from Jenkins GUI and MySQL dump command. Normally we use MySQL dump from CLI or using the windows option. In this case, just automate the MySQL dump triggering from a shell script which will be called by Jenkins job with parameter. MySQL dump needs few parameters to run just pass them by build with parameter option in jenkins.

1. Log to Jenkins default URL and port: http://192.168.56.21:8080/

If you want to install and setup Jenkins see this article

2. Go to New items

3. Give some Name and select FreeStyle project

4. In the build section click on Add build step radio button and select Execute shell.

5. Select boolean parameter for MySQL database host and database superuser password which is root password in MySQL database case.

6. In this build part give the shell script name with full path and parameters like $HOST_IP & $Password

Shell Script

[root@master01 ~]# cat /opt/jenkins_scripts/mysql_full_db_backup.sh
#!/bin/bash
HOST_IP=$1
PASSWORD=$2
echo "starting mysql database full backup"
mysqldump -h $HOST_IP --all-databases --single-transaction --quick --lock-tables=false > /opt/jenkins_scripts/mysql_backup/full_backup_$(date +%F_%N).sql -u root -p$PASSWORD
echo "Backup has been done"

[su_box title=”IMP Note” box_color=”#fe2227″ title_color=”#101112″]Note: Make sure Jenkins have execute (chmod +x /opt/jenkins_scripts/mysql_full_db_backup.sh) privilege on script[/su_box]

7. Let’s execute the Jenkins job

7.1 click on the the MySQL database backup job

7.2 Click on build with Parameter

7.3 Give your database server name or IP. In my case Mysql database running on the same server that’s thy, I will give localhost and database root password

7.4 Once your job is executed go to that job open it in console output mode and check the status of the job. And you are DONE!!!

Apache Tomcat: java.net.BindException: Permission denied (Bind failed) :443

by A. J.

How to fix error: Apache tomcat : java.net.BindException: Permission denied (Bind failed) <null>:443

Full Error:

SEVERE: Failed to initialize end point associated with ProtocolHandler ["http-bio-4443"]
java.net.BindException: Permission denied (Bind failed) <null>:4443
	at org.apache.tomcat.util.net.JIoEndpoint.bind(JIoEndpoint.java:413)
	at org.apache.tomcat.util.net.AbstractEndpoint.init(AbstractEndpoint.java:715)
	at org.apache.coyote.AbstractProtocol.init(AbstractProtocol.java:452)
	at org.apache.coyote.http11.AbstractHttp11JsseProtocol.init(AbstractHttp11JsseProtocol.java:119)
	at org.apache.catalina.connector.Connector.initInternal(Connector.java:978)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.core.StandardService.initInternal(StandardService.java:560)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.core.StandardServer.initInternal(StandardServer.java:840)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.startup.Catalina.load(Catalina.java:642)
	at org.apache.catalina.startup.Catalina.load(Catalina.java:667)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:253)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:427)
Caused by: java.net.BindException: Permission denied (Bind failed)
	at java.net.PlainSocketImpl.socketBind(Native Method)
	at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387)
	at java.net.ServerSocket.bind(ServerSocket.java:390)
	at java.net.ServerSocket.<init>(ServerSocket.java:252)
	at java.net.ServerSocket.<init>(ServerSocket.java:196)
	at javax.net.ssl.SSLServerSocket.<init>(SSLServerSocket.java:136)
	at sun.security.ssl.SSLServerSocketImpl.<init>(SSLServerSocketImpl.java:71)
	at sun.security.ssl.SSLServerSocketFactoryImpl.createServerSocket(SSLServerSocketFactoryImpl.java:80)
	at org.apache.tomcat.util.net.jsse.JSSESocketFactory.createSocket(JSSESocketFactory.java:256)
	at org.apache.tomcat.util.net.JIoEndpoint.bind(JIoEndpoint.java:400)
	... 17 more

Why, when, and where we get this error?

We get this issue while starting Apache tomcat on secure port 443. The error “java.net.BindException: Permission denied (Bind failed) :443 ” is visible in /usr/share/tomcat/logs/catalina.2016-12-02.log

How to fix it

This error occurs when your Linux firewall levels are set to ‘enforcing‘.To fix this error make it ‘permissive‘

Check current firewall status using the command ‘getenforce‘

Edit the file ‘vi /etc/selinux/config’ and make it ‘permissive’ from ‘enforcing’

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#       enforcing - SELinux security policy is enforced.
#       permissive - SELinux prints warnings instead of enforcing.
#       disabled - No SELinux policy is loaded.
SELINUX=permissive
# SELINUXTYPE= can take one of these two values:
#       targeted - Targeted processes are protected,
#       mls - Multi Level Security protection.
SELINUXTYPE=targeted

Reboot the system using ‘reboot‘ as the root
After reboot check, if tomcat is up with 443 port
```
netstat -plan| grep 443
```
And check the tomcat URL with ssl/https (https://localhost:443)

Leave a comment if you find the article helpful.

How to Configure Oracle Transparent Data Encryption (TDE) on Standby Database

by A. J.

How to Configure Oracle Transparent Data Encryption (TDE) on Standby Database

In this article, we will see how to enable Oracle Transparent Data Encryption TDE on the Standby database with easy and simple steps. If we have Oracle Transparent Data Encryption TDE enabled primary database standby database won’t be able to apply the logs. And it may possible that it could out of synchronization from the primary side.

I would recommend enabling Oracle Transparent Data Encryption TDE on standby along with the primary database. If you do it later you might see standby is out of synchronization with Primary database. Rebuilding a big database standby database is a complex and time-consuming task. In this way, you can enable Oracle Transparent Data Encryption TDE with few easy steps. Primary and standby could be TDE enabled in the same downtime window.

Oracle Transparent Data Encryption TDE is one of the ways in Oracle Advanced security to secure the database physical datafiles.

On Standby Database

[su_note note_color=”#0174be” text_color=”#ffffff” radius=”4″]TDE Prerequisites[/su_note]

Make sure OPtach 23315889 has been applied to oracle standby database oracle home

opatch lsinventory| grep 23315889

On Primary Database

1. Login to Primary database and get the wallet path.

SQL>select WRL_PARAMETER from v$encryption_wallet;

WRL_PARAMETER
--------------------------------------------------------------------------------
/u01/oracle/admin/wallet/testdb01/

2. Check the wallet key files.

ls -lrt /u01/oracle/admin/wallet/testdb01

-rw-------. 1 oracle oninstall 2093 Jun 9 06:59 ewallet.p12
-rw-------. 1 oracle oninstall 1928 Jun 9 07:24 cwallet.sso

3. Zip the keys and Copy the files to the standby server.

cd /u01/oracle/admin/wallet/testdb01
zip /tmp/walletkeys.zip *
scp /u01/oracle/admin/wallet/testdb01/*wallet.* 192.168.56.5:/tmp

On Standby Database

1. Go to the Standby data $TNS_ADMIN and add the wallet path.

cd $TNS_ADMIN
vim sqlnet.ora

--add following line

ENCRYPTION_WALLET_LOCATION = (SOURCE = (METHOD = FILE) (METHOD_DATA = (DIRECTORY = /u01/oracle/admin/$ORACLE_SID/wallet/)))

2. Make the directory

mkdir -p /u01/oracle/admin/$ORACLE_SID/wallet/

Note: $ORACLE_SID is your database Name

3. Copy the primary database key to standby wallet location.

cd /tmp
unzip walletkeys.zip
cp /tmp/*wallet*.* /opt/oracle/admin/$ORACLE_SID/wallet/wallet_tde

3. Stop Standby recovery the standby database.

sqlplus "/as sysdba"

SQL> alter database recover managed standby database cancel;

SQL> shutdown immediate

4. Start the standby database in read-only mode.

SQL> Startup;

5. Check wallet path it should be Open and Autologin mode.

SQL> select status,wallet_type from v$encription_wallet;

status wallet_type
--------------------------------
OPEN AUTOLOGIN

6. Prepare the tablespace datafile encryption script.

$ sqlplus / as sysdba
SQL>set heading off
SQL>set linesize 150
SQL>spool tablespace_datafiles_encrypt.sql
SQL>select 'alter database datafile ''' || file_name ||''' encrypt;' from dba_data_files where tablespace_name not in ('SYSTEM','SYSAUX','TEMP1','TEMP2','APPS_UNDOTS1');
SQL>exit

[su_box title=”IMP Note” box_color=”#fe2227″ title_color=”#101112″] Make sure you leave following table space database in encryption script ‘SYSTEM’, ‘SYSAUX’,’TEMP1′,’TEMP2′,’APPS_UNDOTS1′[/su_box]

7. Stop the Standby Database again.

SQL> Shutdown normal;

8. Start the database in mount mode.

SQL> startup mount

9. Run the database encryption script.

SQL> @tablespace_datafiles_encrypt.sql

10. Once Tablespace encrypt script is completed successfully Start the standby recovery.

SQL> alter database recover managed standby database disconnect;

20. Monitor standby log apply. If you see logs are applying properly on standby side. You are Done!

SQL> select process, status, thread#, sequence#, from v$managed_standby;

PROCESS STATUS THREAD# SEQUENCE#
------- ------------ ---------- ----------
MRP0 APPLYING_LOG 1 10293

Hope you will find this article helpful. in case if you have any questions ask me my comments.

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