Upgrading from Debian 8 (Jessie) to Debian 9 (Stretch)

Previously, I looked at setting up Debian 8 with PHP 7.0. But now, Debian 9 is the current stable version and Debian 8 is only due to receive security updates until May 2018. Sounds like a good time to upgrade!

The reason I started to look into upgrading was that I found out that the highest version of Apache available on Debian 8 is Apache 2.4.10 which is not capable of running HTTP/2. Having recently upgraded a lot of my websites to HTTPS, I also wanted to upgrade them to HTTP/2 aswell. Debian 8’s version of Apache was not able to be upgraded without doing so manually. However, Debian 9’s default version of Apache is 2.4.25 which is HTTP/2 capable, it also has PHP 7.0 as the default and has upgraded MySQL to MariaDB. All the more reason to upgrade!

From here…

For those who don’t know, Debian codenames are based on the characters in the famous animated movie Toy Story. This release is named after the glittery purple rubber toy octopus, Stretch.

Alternatives to upgrading to Debian 9 (Stretch)

Upgrading from Debian Jessie to Stretch will not be for everyone. Here are some possible alternatives.

Manually installing a higher version of Apache.

This is generally thought of as possible but not recommended. You also have the gradual winding down of Debian support from May 2018 which may lead to security risks.

Changing to another flavor of Linux with a version of Apache that is capable of running HTTP/2.

Ubuntu 16.04 is one version that can run HTTP/2 without too much tinkering.

Ubuntu is similar to Debian in terms of the shell commands. I have some websites that use Ubuntu 16.04 but for this particular website, I wanted to stay with Debian. Ubuntu is thought of as more experimental, while Debian is thought of as more stable and faster.

Ubuntu 16.04 LTS looks like it will be supported until April 2021 from here so it will not need updating any time soon. The next version with long-term support (LTS) is released next month (April 2018) so I may look into upgrading the servers running Ubuntu when that arrives.

I have used AWS in the past and I have built websites on FreeBSD and CentOS servers that I can remember, but currently I am mainly using Debian and Ubuntu with un-managed VPS. This experience has made me want to try some different flavors, or at least learn about how the other flavors are different. What I’ve read so far makes me think that Debian is a decent choice for this site. Here’s a comparison between Debian, Ubuntu and CentOS for webservers.

Changing from Apache to Nginx.

While you’re still left with the Debian support for Jessie winding down, changing to Nginx is probably a good move. Debian 9 with Nginx may well be faster than it would be with Apache. The version of Nginx you install on Debian 8 with Jessie Backports can run HTTP/2.

The problem with changing to Nginx on a live website is that it is completely different as a webserver to Apache. Nginx does not have .htaccess files and the setup will be different in ways that I’m not aware of yet. I wanted to upgrade in less than a day on this live website so this option was not right for me at the time. But, I do plan to use Nginx in the near future.

Upgrading from Debian 8 (Jessie) to Debian 9 (Stretch)

The official Debian guide to doing this manually in the command line is here. I decided against doing it this way, although it may have lead to less downtime. I decided a fresh install may cause less problems in the future.

I decided to just re-install in the hosting company portal. This meant backing everything up, then with the installation, everything was erased and had to be re-added. There is only one website on the VPS which is a WordPress blog. There was nothing particularly complicated about the server setup which made life a lot easier. The main thing I had to do were to get MariaDB installed and to import the backed up SQL file from the MySQL, I referred to this guide for that. I also had to get Lets Encrypt installed and set up the SSL encryption again.

One of the things I had to change from when I set up Debian 8 with PHP 7.0 was the way PHP 7.0 is installed/served. mpm_prefork is not compatible with HTTP/2 (mod_http2) so I had to use another way of installing PHP (from here).

I was rushing the installation through as quickly as I could because the website was down. I probably did some things in the wrong order and I did encounter some problems. However, after about 45 minutes I had to leave the house and do some chores. At that stage, the WordPress blog was basically up and running but mod_rewrite was not configured correctly yet and the SSL was not set up yet either.

When I got back I started to finish off getting the site working but almost as soon as I sat down the server locked me out of SFTP and SSH. I could not even access the shell on the control panel’s console. I actually thought I’d locked myself out with the UFW firewall. I’m not sure what the problem was but it turned out to just be temporary and I hadn’t locked myself out at all.

Everything went pretty smoothly really. I got the occasional error when trying to reboot but nothing major. Every time it was pretty obvious what the problem was without doing much, if any, investigating. The dreaded error message when Apache won’t restart is definitely becoming less scary these days since I started ignoring the files it tells you to look at and just go straight for the main error.log or whatever you have set up as the main error log file.

Learning New Stuff

I was expecting more problems from exporting the MySQL then importing it into MariaDB. Even if the import/export went smoothly I was expecting to have some issues with WordPress itself. All I can say is no problems whatsoever with the database or WordPress at all. Maybe it’s because I’ve done this kind of thing a few times before and this time I was actually ready and prepared for it.

Because the website is just a WordPress blog I am not going to be doing a huge amount of work with MariaDB on that website. But, one of the things I did take a look at was the MariaDB tuning: mysqltuner. I can’t wait to do some more work with MariaDB in future.

I did all the database backup, set up and importing in the shell. I didn’t use PHPmyAdmin at all but decided to install it at the end incase I ever needed to use it. Then, setting up PHPmyAdmin needed some more shell work with the MySQL command line and MariaDB. Because of all this, I feel like I’m a lot more confident with the MySQL command line.

The Unattended Upgrades file that came with my installation seems to be the same one used with Jessie. Referred to articles such as Unattended Upgrades in Debian 9 for what to keep and what to remove.

Unattended Upgrades will need to send emails to tell you when it needs a reboot unless you have it automatically reboot or just do not want emails. I had the Jessie server set up to send emails directly from the server. This time I decided to send the server emails with Mailgun using this guide.

With trying to get the website up-and-running normally as soon as possible I feel like I got to know Nano a lot better. I even edited the nano config file, /etc/nanorc, to tweak some of the things I have disliked about using Nano.

Issues Encountered

The Sudoers file.

After setting up a user and adding it to the group, sudo, I was getting errors every time I wanted to use a sudo command. I may have done this before but the sudoers file is located at /etc/sudoers

Something like…

root ALL=(ALL:ALL) ALL

Problem installing Python and Let’s Encrypt… dependencies.

Once I’d fixed the Sudoers file I think there may have been another obstacle to installing Python and the Lets Encrypt dependencies but I have completely forgotten what it was.

PHPmyAdmin could not create the phpmyadmin table or the ‘pma’ user.

I did not use PHPmyAdmin at all but installing it at the end caused a few problems that were easily fixed.

Outcome

All-in-all I’m very happy I got the upgrade done. And, I’m pleased I was able to do it fairly quickly despite having to leave the house against my will during the process then getting locked out. I’m looking forward to playing with and configuring Debian 9 Stretch on this VPS. And I think I chose the right way to do the upgrade. Upgrading from Debian 8 Jessie to Debian 9 Stretch on a live website through the shell can be risky and I didn’t want to get to a situation where nothing worked and I didn’t know how to fix it. The cherry on the cake is that I now have HTTP/2 working which was the main thing I wanted to add at the start, plus I have some other upgrades. Debian 9 should be ok for at least a year before I need to start thinking about upgrading again - Debian Version History.

Future

Now, having researched HTTP/2, Debian and Apache for this project I am keen to try Nginx very soon. Nginx is a similar speed as Apache for some things but is much faster in others so I am looking forward to seeing what a life without .htaccess files looks like.