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centos_7_migration_notes [2019/04/30 20:43] juckinscentos_7_migration_notes [2023/12/14 10:10] (current) juckins
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 RHEL5/6/7 Cheatsheet: {{:rhel_5_6_7_cheatsheet_201410.pdf|}} RHEL5/6/7 Cheatsheet: {{:rhel_5_6_7_cheatsheet_201410.pdf|}}
 +
 +[[https://tuxcare.com/extended-lifecycle-support/|Tuxcare's CentOS 7 Extended Support]]
 +
 +
 +14 Dec 2023 (for Dell XPS 8930 tower):
 +  * Updated kernel from kernel-3.10.0-1160.102.1.el7.x86_64 to kernel-3.10.0-1160.105.1.el7.x86_64
 +  * Attempted to rebooted machine but after the BIOS splash screen, only got a blank screen with blinking cursor in upper-left corner 
 +  * Restarted machine using the power button but had same condition
 +  * Restarted once again but at the BIOS splash screen selected F12
 +  * For boot options, chose Boot from Hard Drive and list of kernels appeared
 +  * Chose latest kernel and machine was OK
 +  * After machine was running, did another restart and machine powered up with no issues
 +
 +23 Oct 2023 (for Dell XPS 8930 tower)
 +  * Updated kernel from kernel-3.10.0-1160.99.1.el7.x86_64 to kernel-3.10.0-1160.102.1.el7.x86_64 and then machine would not boot, just blank screen with blinking cursor in upper-left corner
 +  * Powered off machine, unplugged the USB peripheral cables
 +  * Unplugged power cable for 30 seconds
 +  * Rebooted and used F12 to go into BIOS Boot Options
 +  * Tried to boot to Hard Drive but that immediately failed with error 'press any key to reboot'
 +  * After that, the machine booted up OK and the normal selection of kernels appeared
  
 Other fixes: Other fixes:
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   * Disable WiFi LAN connection with ''# nmcli radio wifi off''   * Disable WiFi LAN connection with ''# nmcli radio wifi off''
   * [[https://unix.stackexchange.com/questions/152691/how-to-disable-beep-sound-in-linux-centos-7-command-line|Disable bell]]   * [[https://unix.stackexchange.com/questions/152691/how-to-disable-beep-sound-in-linux-centos-7-command-line|Disable bell]]
 +
 +11 Oct 2020:
 +  * Keep getting errors in python3 script connecting/updating to mariadb server 
 +      * ''OSError: [Errno 99] Cannot assign requested address''
 +      * ''pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on '127.0.0.1' ([Errno 99] Cannot assign requested address)")''
 +  * Updated /etc/my.cnf.d/server.cnf with this setting under [mariadb-5.5]
 +
 +  max_connections = 818 (Note that 818 seems to be the absolute limit)
 +  back_log = 1024 (Note that OS limit is in /proc/sys/net/ipv4/tcp_max_syn_backlog)
 +  thread_cache_size = 818
 +  thread_handling = pool-of-threads
 +  
 +Then do: ''systemctl restart mariadb.service''
 +
 +  * Other commands to check and modify on mariadb server:
 +      * ''show variables like "max_connections";''
 +      * ''show global status like "Threads_connected";''
 +      * ''show status like "Conn%";''
 +      * ''show status like "Threads%";''
 +      * ''show global status;''
 +  * See https://mariadb.com/kb/en/configuring-mariadb-for-optimal-performance/
 +  * Also check python3 coding best practices for opening/closing database connections
 +    * I have noted that opening and closing the database connection only once in the python script helps reduce database "cannot assign requested address" errors
 +  * [[https://pypi.org/project/mysqlclient/|mysqlclient]] is supposedly [[https://stackoverflow.com/questions/43102442/whats-the-difference-between-mysqldb-mysqlclient-and-mysql-connector-python|faster than alternatives]]
 +      * import MySQLdb
 +      * See examples at https://www.tutorialspoint.com/python/python_database_access.htm
 +
 +  #!/usr/bin/python
 +  
 +  import MySQLdb
 +  
 +  # Open database connection
 +  db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )
 +  
 +  # prepare a cursor object using cursor() method
 +  cursor = db.cursor()
 +  
 +  # execute SQL query using execute() method.
 +  cursor.execute("SELECT VERSION()")
 +  
 +  # Fetch a single row using fetchone() method.
 +  data = cursor.fetchone()
 +  print "Database version : %s " % data
 +  
 +  # disconnect from server
 +  db.close()
 +
 +
 +16 May 2020:
 +  * System randomly reboots when KVM toggles back and forth from Dell XPS 8930 (running CentOS 7 as 'tidewater') and HP Pavilion P7-1240
 +    * Workaround: Use remmina to RDP to local Windows machine
 +  * Noticed monitoring emails not being sent from tidewater; postfix not running and won't start. mysql error.
 +  * yum reinstall <mysql_package> that was failing
 +  * postfix started
 +  * Other trouble...had to completely uninstall PHP
 +  * Reinstall PHP - that is v5.4
 +  * Then upgrade to REMI php v7.4
 +  * Look in the bash setup script to install the needed php files
 +  * Restore /etc/php.ini from a local VM
 +  * restart httpd service
 +  * yum update had many instances of 'empty files'....it fixed itself
 +  * ldconfig gave errors for 2 more things
 +    * yum reinstall oniguruma5
 +    * yum reinstall oniguruma
 +  * reboot system, came up cleanly
 +  * may need to check if mysql connection limit needs to be increased
 +
  
 13 December 2016: 13 December 2016:
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     * [[http://www.uptimemadeeasy.com/linux/mysql-migrate-users-server-server/|Migrate MySQL users to new machine]]     * [[http://www.uptimemadeeasy.com/linux/mysql-migrate-users-server-server/|Migrate MySQL users to new machine]]
       * Don't forget to add semicolons with this:  # sed -i ‘/[^;] *$/s/$/;/’ ./grantfile       * Don't forget to add semicolons with this:  # sed -i ‘/[^;] *$/s/$/;/’ ./grantfile
 +      * Note: I used phpMyAdmin to export users from a VM (get the SQL syntax) and then run that on the new machine
   * export MySQL databases with mysqldump   * export MySQL databases with mysqldump
     * [[https://www.digitalocean.com/community/tutorials/how-to-migrate-a-mysql-database-between-two-servers|Migrate MySQL database to new server]]     * [[https://www.digitalocean.com/community/tutorials/how-to-migrate-a-mysql-database-between-two-servers|Migrate MySQL database to new server]]
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   * list of installed perl modules   * list of installed perl modules
     * grep all .pl script and look for the "use " calls     * grep all .pl script and look for the "use " calls
 +  * list of installed python (pip) modules
   * Copy the following to accessible location for restore after upgrade   * Copy the following to accessible location for restore after upgrade
     * users' $HOME     * users' $HOME
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     * /etc/hosts     * /etc/hosts
     * /etc/httpd/conf/httpd.conf     * /etc/httpd/conf/httpd.conf
-    * /etc/samba/smb.conf +    * Samba users, passwords, shares (for security cameras) 
-      * Samba users, passwords, shares +      * /etc/samba/smb.conf 
-  * nxclient-3.5.0-7.x86_64.rpm +        * smbpasswd -a <username> 
-  * nxnode-3.5.0-9.x86_64.rpm +          * <password> 
-  * nxserver-3.5.0-11.x86_64.rpm+      * /var/lib/samba/private/passdb.tbd 
 +      * /var/lib/samba/private/secrets.tbd 
 +      * Make sure service is running and will start at boot. 
 +      * Check output with: testparm -v 
 +  * <del>nxclient-3.5.0-7.x86_64.rpm</del> 
 +  * <del>nxnode-3.5.0-9.x86_64.rpm</del> 
 +  * <del>nxserver-3.5.0-11.x86_64.rpm</del>
   * <del>skype-4.3.0.37-fedora.i586.rpm</del>   * <del>skype-4.3.0.37-fedora.i586.rpm</del>
   * verify services that should be installed/running in chkconfig   * verify services that should be installed/running in chkconfig
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   * [[gmail_as_a_relay_on_linux|Set up Gmail Relay and test]]   * [[gmail_as_a_relay_on_linux|Set up Gmail Relay and test]]
   * Disable SELinux   * Disable SELinux
-  * VSFTP +  * VSFTP (for security cameras)
     * [[http://www.liquidweb.com/kb/how-to-install-and-configure-vsftpd-on-centos-7/|Config instructions]]     * [[http://www.liquidweb.com/kb/how-to-install-and-configure-vsftpd-on-centos-7/|Config instructions]]
     * [[https://www.benscobie.com/fixing-500-oops-vsftpd-refusing-to-run-with-writable-root-inside-chroot/|500 writeable root error]]     * [[https://www.benscobie.com/fixing-500-oops-vsftpd-refusing-to-run-with-writable-root-inside-chroot/|500 writeable root error]]
-    * As root: setsebool -P allow_ftpd_full_access on +    * As root (if selinux is enabled): setsebool -P allow_ftpd_full_access on 
     * As root: systemctl restart vsftpd     * As root: systemctl restart vsftpd
 +    * As root: systemctl enable vsftpd
   * Samba   * Samba
-    * [[http://www.unixmen.com/install-configure-samba-server-centos-7/|UnixMen.com - Samba on CentOS 7]] +    * [[samba_file_sharing|Samba File Sharing]]
-    * [[https://www.howtoforge.com/samba-server-installation-and-configuration-on-centos-7|HowToForge - Samba on CentOS 7]]+
   * <del>Skype</del>   * <del>Skype</del>
   * Virtual Box   * Virtual Box
   * Working crontabs for each user   * Working crontabs for each user
 +  * [[python_notes|Install Python 3]]
 +
 +Optional:
 +  * [[https://gorilla.dp100.com/downloads/|Password Gorilla]] (use standalone executable)
  
 Contents of /etc/yum.repos.d (CentOS 7): Contents of /etc/yum.repos.d (CentOS 7):
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   * Preferable to use local .iso file to conserve bandwidth for multiple installs    * Preferable to use local .iso file to conserve bandwidth for multiple installs 
-  * Used http://mirror.centos.org/centos/7.1.1503/os/x86_64/ for package repository+  * Used http://mirrors.sonic.net/centos/7.7.1908/os/x86_64/ for package repository
   * On initial config screen, ensure the network connection is activated   * On initial config screen, ensure the network connection is activated
   * You can also disable SELinux   * You can also disable SELinux
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     * Yet another option is to use modules that are in a repository     * Yet another option is to use modules that are in a repository
  
-[[http://www.if-not-true-then-false.com/2010/install-adobe-flash-player-10-on-fedora-centos-red-hat-rhel/|Ensure Adobe Flash plugin is installed]]+<del>[[http://www.if-not-true-then-false.com/2010/install-adobe-flash-player-10-on-fedora-centos-red-hat-rhel/|Ensure Adobe Flash plugin is installed]]</del>
  
 [[http://www.cyberciti.biz/faq/howto-install-linux-apache-mariadb-php-lamp-stack-on-centos7-rhel7/|Ensure Apache is installed and running]] [[http://www.cyberciti.biz/faq/howto-install-linux-apache-mariadb-php-lamp-stack-on-centos7-rhel7/|Ensure Apache is installed and running]]
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   * [[http://howtolamp.com/lamp/httpd/2.4/customizing/|Tips for users and permissions #2]]   * [[http://howtolamp.com/lamp/httpd/2.4/customizing/|Tips for users and permissions #2]]
  
-[[centos_php7.2_upgrade|Upgrade PHP to version 7.2]]+<del>[[centos_php7.2_upgrade|Upgrade PHP to version 7.2]]</del> 
 + 
 +[[https://computingforgeeks.com/how-to-install-php-7-4-on-centos-7/|Upgrade PHP to version 7.4]]
  
 Migrate /etc/php.ini from old server and relax settings due to test env: Migrate /etc/php.ini from old server and relax settings due to test env:
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 Database work: Database work:
 +  * Update /etc/my.cnf.d/server.cnf with this setting under [mariadb-5.5]
 +    * ''max_connections = 800''
 +    * ''systemctl restart mariadb.service''
   * Backup /etc/my.cnf   * Backup /etc/my.cnf
     * Add this line under [mysqld]     * Add this line under [mysqld]
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     * Ensure database on target server exists; create if necessary     * Ensure database on target server exists; create if necessary
       * Tables migrated should be MyISAM       * Tables migrated should be MyISAM
-      * Default database engine is InnoDB as<color #ed1c24>Red Highlighted Text</color> of MySQL 5.5+      * Default database engine is <color #ed1c24>InnoDB</color> as of MySQL 5.5
       * [[https://dev.mysql.com/doc/refman/5.6/en/innodb-default-se.html|Perform some tests and queries]]       * [[https://dev.mysql.com/doc/refman/5.6/en/innodb-default-se.html|Perform some tests and queries]]
         * The exact number of rows of InnoDB tables cannot be shown         * The exact number of rows of InnoDB tables cannot be shown
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       * systemctl start mariadb.service       * systemctl start mariadb.service
       * systemctl enable mariadb.service       * systemctl enable mariadb.service
-    * mysql DATABASE -h localhost -u USER -p'PASS' < /tmp/DATABASE.sql+    * mysql -u USER -p'PASSWORD' (to login to mysql at command line) 
 +      * CREATE DATABASE database_name; 
 +      * Now logout of command line 
 +    * mysql DATABASE_NAME -h localhost -u USER -p'PASS' < /tmp/DATABASE.sql
  
   * Note CentOS7 comes with PHP 5.4 and latest version of phpMyAdmin that will work is 4.4.x   * Note CentOS7 comes with PHP 5.4 and latest version of phpMyAdmin that will work is 4.4.x
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   * https://sourceforge.net/p/ddclient/wiki/Home/   * https://sourceforge.net/p/ddclient/wiki/Home/
   * yum -y install ddclient   * yum -y install ddclient
-  * Use /etc/ddclient/* for configs from previous machine+  * In /etc use the ddclient* files for configs from previous machine
  
 Setup duckdns: Setup duckdns:
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 Setup ydns: Setup ydns:
 +  * crontab is <code>~/ydns/updater.sh -V -u <snip> -p <snip> -H juckins.ydns.eu >>~/ydns/updater.log 2>&1</code>
  
 Firewall notes: Firewall notes:
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   * Additional tips: http://ubuntuforums.org/archive/index.php/t-941530.html   * Additional tips: http://ubuntuforums.org/archive/index.php/t-941530.html
   * systemctl restart sshd.service   * systemctl restart sshd.service
 +  * User accounts at remove machines connecting to the new machine will need their $HOME/.ssh/known_hosts either rebuilt or offending entries removed
  
 Update GRUB and splash screen Update GRUB and splash screen
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   * vi grub    * vi grub 
     * remove "rhgb quiet" from the GRUB_CMDLINE_LINUX call     * remove "rhgb quiet" from the GRUB_CMDLINE_LINUX call
-    * add "vga=0x317" to the GRUB_CMDLINE_LINUX call for better screen resolution (or 0x34b for 1920x1200x8, or vga=ask to see all available resolutions)+    * add "vga=0x317" to the GRUB_CMDLINE_LINUX call for better screen resolution (try 0x34b for 1920x1200x8 or 0x34c for 1920x1200x16, or vga=ask to see all available resolutions)
     * comment out this line: GRUB_TERMINAL_OUTPUT="console"     * comment out this line: GRUB_TERMINAL_OUTPUT="console"
     * add this line: GRUB_BACKGROUND="/boot/grub2/splash.png"     * add this line: GRUB_BACKGROUND="/boot/grub2/splash.png"
       * Ensure it is rw-r-r permissions       * Ensure it is rw-r-r permissions
       * [[http://192.168.1.14/dokuwiki/lib/exe/fetch.php?media=splash.png|Upload this image]] to the directory noted above       * [[http://192.168.1.14/dokuwiki/lib/exe/fetch.php?media=splash.png|Upload this image]] to the directory noted above
-  * For VM/BIOS-based installs, as root: grub2-mkconfig -o /boot/grub2/grub.cfg+  * For VM/BIOS-based installs, as root: grub2-mkconfig -o /boot/grub2/grub.cfg (Dell XPS 8930)
   * For UEFI-based installs, as root: grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg   * For UEFI-based installs, as root: grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
   * More info at [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Customizing_the_GRUB_2_Configuration_File.html|Customizing the Grub2 Config File]] and [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Desktop_Migration_and_Administration_Guide/GRUB.html|RHEL7 GRUB Guide]]   * More info at [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Customizing_the_GRUB_2_Configuration_File.html|Customizing the Grub2 Config File]] and [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Desktop_Migration_and_Administration_Guide/GRUB.html|RHEL7 GRUB Guide]]
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 Set up local printer(s) Set up local printer(s)
 +  * Note that Brother has notes for the HL2170W at https://support.brother.com/g/b/downloadlist.aspx?c=us&lang=en&prod=hl2170w_all&os=127
 +    * RPM #1: brhl2170wlpr-2.0.2-1.i386.rpm
 +    * RPM #2: cupswrapperHL2170W-2.0.2-1.i386.rpm
 +    * Use 'lpstat' and 'lpq' to ensure it's a known destination printer
   * [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Printer_Configuration.html#sec-Starting_Print_Settings_Config|RHEL7 Print Settings]]   * [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Printer_Configuration.html#sec-Starting_Print_Settings_Config|RHEL7 Print Settings]]
   * yum install cups   * yum install cups
centos_7_migration_notes.1556671432.txt.gz · Last modified: 2019/04/30 20:43 by juckins