Intro
I’m thrilled to announce that the long-running blog drjohnstechtalk.com has now been migrated to a modern back-end operating system. drjohnetchtalk.com is, a far as I know, the only quality-written technical resource on the Internet which is not supported by ads. Instead it runs on a pay-it-forward approach, embracing the spirit of the old Internet before it was ruined by big money.
drjohnstechtalk.com has been providing solutions to obscure tech questions since 2011.
The details
I like to run my own server which I can use for other purposes as well. I think that approach used to be more common. Now it’s harder to find others using it. Anyway, my old hosting environment is a CentOS server. I had hoped it would last me up to 10 years! 10 years is about the duration of long-term support for Redhat linux. It’s a real pain to migrate a WordPress blog with lots of history where it is important to preserve the articles and the permalinks. This article documents the nightmare I put myself through to get that up and running. Before that there was a CentOS 6 server. Then in 2022 – only about two years later – I learned that CentOS was dead! IBM had killed it. I’m over-simplifying here somewhat, but not by much.
So my blog sort of limped on on this unsupported system, getting riskier by the day to run as I was missing out on security patches. Then my companyt accidentally included one of my blogs in a security scan and I saw I had some vulnerabilities. So I upgraded WordPress versions and plugin versions. So with up to date software, the stage was set to migrate to a newer OS. Further motivation was provided by the fact that after the WP upgrade, the pages loaded more slowly. And sometimes the site just collapsed and crashed.
I have come to love Debian linux due to my positive experience with running it on Raspberry Pis and a few other places. It tends to run more recent versions of open source software, for instance. So I chose a Debian linux server. Then I forget where I learned this. Perhaps I asked someone at work which web server to use, but the advice was to use nginx, not apache! This was very new to me as I had never run nginx, not that I was in love with apache.
So, anyway, here I am writing this on my shiny new Debian 12 bookworm server which is running an nginx web server! And wow my site loads so much faster now. It’s really striking…
Running WordPress in a subdirectory with nginx
There always has to be a hard part, right? This was really, really hard. I run WP in the subdirectory blog as you can see from any of my URLs. I must have scoured a dozen sites on how to do it, none of which completely worked for me. So I had to do at least some of the heavy lifting and work out a working config on my own.
Here it is:
# mostly taken from https://www.nginx.com/resources/wiki/start/topics/recipes/wordpress/
# but with some important mods
upstream php {
server unix:/var/run/php/php8.2-fpm.sock;
}
server {
listen 443 ssl;
include snippets/self-signed.conf;
server_name drjohnstechtalk.com www.drjohnstechtalk.com;
root /web/drjohns;
index index.php index.html;
access_log /var/log/nginx/drjohns.access.log;
error_log /var/log/nginx/drjohns.error.log;
client_max_body_size 100M;
# the following section prevents wp-admin from infintely redirecting to itself!
location /blog/wp-admin {
root /web/drjohns;
try_files $uri $uri/ /blog/wp-admin/index.php?$args;
}
location /blog {
root /web/drjohns/blog;
try_files $uri $uri/ /blog/index.php?$args;
}
location ~ \.php$ {
#NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
include fastcgi_params;
fastcgi_intercept_errors on;
fastcgi_pass php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}
location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg) {
expires max;
log_not_found off;
}
}
I had to add ths svg file type to ignore, the location directive that matches /blog/wp-admin/. I had to define the upstream label as php and refer to that label in fastcgi_pass. I had to figure out my correct version of fastcgi. I tossed out some location directives which weren’t too important to me.
I disabled the wp-hide-login plugin while I grappled with why I was getting first a 404 not found for /blog/wp-admin/, then later, the too many redirects error. But I still had the issue with it disabled. Once I resolved the problem by adding the /blog/wp-admin location directive – I seem to be the only one on the Internet offering this solution and no other solution worked for me! – then I re-enabled the hide login plugin. The other plugins are working I would say.
Firewall?
I gather the current approach to host-based firewall on Debian 12 is to run ufw. A really good article on setting it up is here: https://www.cyberciti.biz/faq/set-up-a-firewall-with-ufw-on-debian-12-linux/
I’m on the fence about it, fearing it might slow my speedy server. But it looks pretty good. So for now I am relying on AWS Network Security Group rules. Did you know you can ask them to increase your max rule quota frmo 20 to 40? Yes, you can. I did and got approved overnight. I have added the Cloudflare ranges.
Cloudflare
I continue to use Cloudflare as reverse proxy, certificate issuer, DNS provider and light security screening. The change to the new server did not alter that. But I needed a new config file to properly report the origin IP address in my access files. The following file does the trick for me. It is up to date as of February 2024, can be placed in your /etc/nginx/conf.d directory and called, e.g., cloudlfare.conf.
# up to date as of 2/2024
set_real_ip_from 103.21.244.0/22;
set_real_ip_from 103.22.200.0/22;
set_real_ip_from 103.31.4.0/22;
set_real_ip_from 104.16.0.0/13;
set_real_ip_from 104.24.0.0/14;
set_real_ip_from 108.162.192.0/18;
set_real_ip_from 131.0.72.0/22;
set_real_ip_from 141.101.64.0/18;
set_real_ip_from 162.158.0.0/15;
set_real_ip_from 172.64.0.0/13;
set_real_ip_from 173.245.48.0/20;
set_real_ip_from 188.114.96.0/20;
set_real_ip_from 190.93.240.0/20;
set_real_ip_from 197.234.240.0/22;
set_real_ip_from 198.41.128.0/17;
set_real_ip_from 2400:cb00::/32;
set_real_ip_from 2606:4700::/32;
set_real_ip_from 2803:f800::/32;
set_real_ip_from 2405:b500::/32;
set_real_ip_from 2405:8100::/32;
set_real_ip_from 2c0f:f248::/32;
set_real_ip_from 2a06:98c0::/29;
real_ip_header CF-Connecting-IP;
The idea is that if the source IP of the HTTP connection to nginx is from the Cloudflare range of IPs, then this must represent a request proxied through Cloudflare and the original IP of the client is in the HTTP header CF-Connecting-IP, which nginx can report on. If not, just use the normal IP from the TCP connection.
Swap space
On CentOS I had to provide some swap space because otherwise apache + mariaDB + WordPress would easily send its cpu soaring. So far I have not had to do that with my new Debian 12! That is great… So I have a t2.small instance with 25 GB of gp2 storage (100 iops). The server is basically running with a 0.00 load average now. I don’t get a lot of traffic so I hope that infrastructure will suffice.
Set the timezone
My Debian system started out in the UTC timezone. This command confirms that:
sudo timedatectl
This command brings up a menu and i can change the timezone to US Eastern:
sudo dpkg-reconfigure tzdata
Automate patching
It hasn’t run yet, but I’m hoping this root crontab entry will automate the system updates:
59 2 * * 0 (date && apt-get update && apt-get upgrade -y) >> /home/admin/hosting/update.log 2>&1
Debian 12 lifecycle
There should be three years of full support plus two more years of long term support for a stable Debian release, if I’ve undrstood it correctly. So I believe I may hope to get five years out of my Bookworm version, give or take. Debian — Debian Releases
Fixing the vi editor
I’ve never really had a problem with vi until this server. I show how I fixed it in this blog post.
Status after a few days – not all positive news
Well after a few days I feel the server response has noticeably slowed. I could not run top because I messed up the terminal with my fix to vi! So in a panic I restarted mariadb which seemed to help performance a lot. I will have to figure out how to monitor for this problem and how best to address it. I’m sure it will return. Here is my monitor.sh script:
#!/bin/bash
# restart mariaDB if home page response becomes greater than one second
curl -m1 -o /dev/null -ksH 'Host:drjohnstechtalk.com' https://localhost/blog/
# if curl didn't have enough time (one sec), its exit status is 28
[ $? -eq 28 ] && (systemctl stop mariadb; sleep 3; systemctl start mariadb; echo mariadb restart at $(date))
I invoke it from root’s crontab every three minutes:
# check that our load time is within reason or else restart mariadb -DrJ 2/24 */3 * * * * sleep 25;cd /home/admin/hosting; ./monitor.sh >> monitor.log 2>&1
I do love my kludges. I will be on the lookout for a better long-term solution.
Conclusion
The technical blogging web site drjohnstechtalk.com now runs on new infrastructure: Debian 12 running nginx. It is muich faster than before. The migration was moderately painful! I have shared the technical details on how I managed to do it. I hope that, unlike my previous platform of CentOS 8, this platform lasts me for the next 10 years!
References and related
nginx’s own advice about how to configure it to run WordPress
Trying to upgrade WordPress brings a thicket of problems
One of many RPi projects of mine: Raspberry Pi light sensor project
