hosting – Page 4 – Kev's Development Toolbox

July 19, 2017July 19, 2017

Manually disabling WordPress plugins

If you’re adding new plugins to your WordPress site, depending on the plugin type you can end up with your site being inaccessible if the plugin configuration is wrong. A good example is adding Google’s reCAPTCHA plugin. If you activate the plugin but the config is not correct, for example if your site id is not matching your domain name, AND if you’ve added the reCAPTCHA on your login form, you can end up in a position where you’re completely unable to log on to your site.

Luckily if you can ssh into your server, you can disable a plugin easily by just removing or renaming the plugin folder, for example in your wp-content/plugins folder.

Comparing nginx memory usage to apache2

I’ve trimmed down my apache conf to work ok for a small site, but after uploading my exported data from my old site to my new, the 4x apache2 processes have grown considerably and consumed all my VPS memory. Knowing nginx has a much lighter footprint, I wondered what it would look like in comparison.

Here’s the memory usage after completing my exported data file imports – I get that after completing this imports to the new site this is the memory usage of the apache processes after load from importing about 20x 10MB xml export files. At idle after a restart the memory usage does start considerably lower, but here’s where I’m at right now:

$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r
%MEM %CPU   RSS    VSZ COMMAND
32.2  1.7 169228 904300 /usr/sbin/mysqld
24.5  1.2 128684 385360 /usr/sbin/apache2 -k start
20.2  0.2 105968 355004 /usr/sbin/apache2 -k start
18.4  4.0 96740 352540 /usr/sbin/apache2 -k start
 2.5  0.0 13144 283312 /usr/sbin/apache2 -k start

So following the guide here just to install nginx and the fastcgi php, and then here for WordPress specific config, here’s what it looked like on restart:

$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r
%MEM %CPU   RSS    VSZ COMMAND
 9.3  0.4 49124 576488 /usr/sbin/mysqld
 6.0  0.0 31516 235504 php-fpm: pool www                                                       
 4.5  0.0 23860 232660 php-fpm: pool www                                                       
 2.6  0.0 14032 230016 php-fpm: master process (/etc/php5/fpm/php-fpm.conf)                    
 0.5  0.0  2804  86472 nginx: worker process
 0.3  0.0  2004  86128 nginx: worker process
 0.3  0.0  2004  86128 nginx: worker process
 0.3  0.0  1988  86128 nginx: worker process
 0.3  0.0  1900  33188 init
 0.2  0.0  1452  85832 nginx: master process /usr/sbin/nginx

This is looking better, still need to work on getting the mysql usage down, but at least now I’m not maxed out:

$ free
             total       used       free     shared    buffers     cached
Mem:        524288     431192      93096      68180          0     259440
-/+ buffers/cache:     171752     352536
Swap:            0          0          0

July 13, 2017

Reducing memory usage by Apache and MySql in a 512MB VPS

Installing with the default Apache and MySQL configurations, you end up with far too many idle Apache threads, and MySQL is the largest memory user by far. The default config of these two is maxing out my available 512MB in my VPS server:

/etc/apache2$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r       

%MEM %CPU   RSS    VSZ COMMAND
 9.5  0.0 49904 720256 /usr/sbin/mysqld
 6.7  0.0 35620 286860 /usr/sbin/apache2 -k start
 6.5  0.0 34452 283524 /usr/sbin/apache2 -k start
 6.2  0.0 32692 283012 /usr/sbin/apache2 -k start
 5.9  0.0 31276 283116 /usr/sbin/apache2 -k start
 5.8  0.0 30896 282652 /usr/sbin/apache2 -k start
 5.0  0.0 26724 282588 /usr/sbin/apache2 -k start
 4.8  0.0 25204 279552 /usr/sbin/apache2 -k start
 4.8  0.0 25200 279552 /usr/sbin/apache2 -k start
 4.7  0.0 25156 279508 /usr/sbin/apache2 -k start
 4.4  0.0 23216 279540 /usr/sbin/apache2 -k start
 2.8  0.0 15136 278400 /usr/sbin/apache2 -k start
 0.7  0.0  3968  90908 sshd: myuser [priv] 
 0.4  0.0  2564  61312 /usr/sbin/sshd -D
 0.4  0.0  2264  33188 init
 0.3  0.0  2060  18128 -bash
...

/etc/apache2$ free
             total       used       free     shared    buffers     cached
Mem:        524288     476496      47792      68220          0     260764
-/+ buffers/cache:     215732     308556
Swap:            0          0          0

From tips in this article, I reduced down the Apache threads and now we’re at:

/etc/apache2/mods-enabled$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r
%MEM %CPU   RSS    VSZ COMMAND
 9.5  0.0 49904 720256 /usr/sbin/mysqld
 2.8  0.0 15132 278400 /usr/sbin/apache2 -k start
 1.1  0.0  6004 278424 /usr/sbin/apache2 -k start
 0.7  0.0  3968  90908 sshd: myuser [priv] 
 0.4  0.0  2564  61312 /usr/sbin/sshd -D
 0.4  0.0  2264  33188 init
 0.3  0.0  2076  18136 -bash

/etc/apache2/mods-enabled$ free
             total       used       free     shared    buffers     cached
Mem:        524288     400244     124044      68220          0     262480
-/+ buffers/cache:     137764     386524
Swap:            0          0          0

Now we’ve got some free space, and definitely not maxing out our available ram. Next up, I’ll take a look at MySQL.

July 12, 2017

Setting up WordPress on Apache and MySql on a Linux VPS host

I’ve run this blog for the past couple of years on OpenShift Online. I’ve been excited that the new Online v3 is moving to a container based service, but the cost per month is now much more than I wanted to pay. I was about to setup WordPress on AWS in an EC2 instance (if for nothing more than to get some experience playing with EC2), but after posting on Twitter for suggestions, there was a suggestion to check out cheap Virtual Private Server (VPS) offerings. The lowendbox.com site covers many offers from hosting companies offering VPS based services, so I took a look and picked up a 2 CPU core, 512MB, 200GB disk VPS for $2.50 a month. That’s a manageable cost and looks like a comparably price for a low end VPS server.

To get started after provisioning my VPS , I created a new user with sudo access instead of using the default root user created on initial setup:

```
adduser newuser
```
```
usermod -aG sudo newuser
```

On my Ubuntu 14.04 minimal server install, apparently even sudo is not yet installed, so per steps here, su’d to root, and then installed sudo:

```
su -
```
```
apt-get update
```
```
apt-get install sudo
```

Installed mysql-server. There’s many guides for installing MySQL, but here’s one as a reference.

```
sudo apt-get update
```
```
sudo apt-get install mysql-server
```

During installation I got this error, and the server failed to start during installation:

/var/lib/dpkg/info/mysql-server-5.5.postinst: line 150: logger: command not found
ATTENTION: An error has occured. More info is in the syslog!

From this post here, the fix is to:

```
apt-get --reinstall install bsdutils
```

As this ran, the mysql install started showing additional input and the server started up.

Next, setup:

```
sudo mysql_secure_installation
```

Followed the prompts and remove anonymous user access, test database etc.

Created a new MySQL database with user/password that WordPress will use to access the database, following steps here.

Installed apache:

sudo apt-get install apache2

Installed php modules for apache:

sudo apt-get install php5 libapache2-mod-php5

Hitting the WordPress setup url, got this error:

Your PHP installation appears to be missing the MySQL extension which is required by WordPress.

This is fixed by installing the php mysql package (discussed here):

apt-get install php5-mysql

Installing WordPress from scratch is covered in detail here. The only additional step I needed to do was to tell Apache to server index.php so you’d see the WordPress site when hitting the site root url.

This can be done by editing /etc/apache2/apache2.conf and adding a DirectoryIndex:

<Directory /var/www/>
        Options Indexes FollowSymLinks
        AllowOverride None
        DirectoryIndex index.php
        Require all granted
</Directory>

Restart apache and you should be up and running:

sudo service apache2 restart

As start this is pretty good. It looks like the default apache and mysql settings are maxing out my 512MB so I’ve got some tuning to do, and then I need to migrate my WordPress database across, but so far so good!