Debian 9 Stretch release : upgrade & new features
As Debian recently released its new stable version 9 (« Stretch »), we decided to give it a run on some of our servers and are pleased with the results. Debian has long been our « go-to OS » for reasons of its excellent stability and performance in a data centre environment, and it looks like Debian 9 Stretch will soon become the default OS in our new server installations. This release will be supported until mid 2022 which is a definite decision criterion for its selection.
As always, the release comes with many updates and a large eco-system of software packages that have been updated. The fact that you can now EUFI-boot a debian 9 live image is a very good start. The kernel desperately needed to be upgraded from 3.16 and 4.9 is the right choice. The packaged Xen Hypervisor leaped forward from 4.4 to 4.8 which is relevant to Syloé as we host many Xen-VMs. There are many relevant security and driver updates in the kernel 4.9 and features provided by the upgraded system. We also welcome the package upgrades affecting a major part of our customer-base : Apache, Perl, MariaDB, PHP, PostgreSQL, Tomcat, Python, OpenJDK, Ruby and such.
The official Debian 9 Stretch Feature List
Most of these packages will upgrade without any issues. However – naturally there are always some gotcha’s you need to be aware off – and stepping back is not always as easy as stepping forward. Some of the most noteworthy upgrades that can have a considerable impact are :
* PHP. Your code has to be PHP 7 compatible – otherwise your debian upgrade will end in a test of your rollback procedures.
* MySQL. The upgrade to Stretch will change MySQL 5 to MariaDB 10.1 and there are some pitfalls to be avoided there.
* PostgreSQL. Not anything major compared to MySQL but still important to migrate the database outside of the APT cycle and be aware of changes in the systemd service management configuration.
There is always the possibility to exclude certain packages from the upgrade and perform these later after a procedure has been properly tested in a controlled environment. Backups, database dumps and LVM snapshots are crucial to secure a fail-safe when required.
At Syloé, we have a keen understanding of our customers services and are often asked to develop and perform customized upgrade procedures for major system upgrades to production systems. The upgrade to Debian 9 Stretch will offer many benefits and can be performed seamlessly, when properly managed. We recommend you evaluate its benefits and don’t hesitate to give us a call or contact us if stretched thin on resources..