Add in-place MariaDB upgrade note

Signed-off-by: Anatoli Nicolae <[email protected]>

notes/in-place-mariadb-upgrade.md

@@ -0,0 +1,78 @@
+---
+title: In-place MariaDB upgrade
+tags:
+  - mariadb
+  - database
+  - systemd
+emoji: 🦭
+queries:
+  - in-place mariadb upgrade
+---
+
+<Warning>
+
+This procedure is **highly discouraged** as it may lead to serious data loss.
+
+</Warning>
+
+<Note>
+
+Take advantage of the [zero downtime migration tool](https://docs.apiscp.com/admin/Migrations%20-%20server/#migration-components) to get those sites over that need the newer MariaDB release while evaluating the impact it can have.
+
+</Note>
+
+<Warning>
+
+If you still chose to proceed with an in-place migration, **make sure your data is backed up before proceeding.**
+
+</Warning>
+
+## Checklist
+- [ ] Set maintenance window
+- [ ] upcp -sb 1 hour before maintenance, to make sure everything works
+- [ ] Do all steps in exact order
+- [ ] Take notes on behaviour
+
+
+## Procedure
+
+```bash
+# Run bootstrapper
+upcp -sb
+
+# Set new MariaDB version
+cpcmd scope:set cp.bootstrapper mariadb_version 10.11
+
+# Make a copy of the repo definition
+mysql -v
+cat /etc/yum.repos.d/mariadb.repo
+mv /etc/yum.repos.d/mariadb.repo{,.bak}
+
+# Install new MariaDB version
+upcp -sb
+
+dnf update -y
+
+# Perform a backup of all databases
+mysqldump --opt --all-databases --routines --events -r /home/all-$(date +%F-%T).sql
+
+# Stop MariaDB service
+systemctl stop mariadb.service
+
+# Look up newest MariaDB-server version, and install it
+rpm -e $(rpm -qa | grep -i '^MariaDB-server')
+dnf install MariaDB-server-10.11.2-1.el8.x86_64 -y
+
+# Fix logs permissions
+chown mysql /var/log/mysql
+
+# Start MariaDB service again
+systemctl start mariadb.service
+
+# Perform the upgrade using MariDB's utility
+mysql_upgrade
+mysql_upgrade -f -k --upgrade-system-tables
+
+# Make sure the service is properly running
+systemctl status mariadb.service
+```

notes/install-memcached.md

@@ -5,6 +5,7 @@ tags:
   - cache
   - memcached
   - optimizations
+emoji: 🧠
 link: https://github.com/thundersquared/apiscp-memcached
 queries:
   - how to install memcached