Difference between revisions of "WeBWorK 2.15 Ubuntu Server 20.04 LTS Amazon Machine Image"

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'''Do not forget the <code>&lt;new wwadmin password&gt;</code> that you just entered.''' Below when we refer to <wwadmin password>, we mean the '''new'''<wwadmin password> (<new wwadmin password>).
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'''Do not forget the <code>&lt;new wwadmin password&gt;</code> that you just entered.''' Below when we refer to <wwadmin password>, we mean the '''new''' <wwadmin password> (<new wwadmin password>).
   
 
====Change the password for webworkWrite====
 
====Change the password for webworkWrite====

Revision as of 14:17, 24 June 2020


Construction.png This article is under construction. Use the information herein with caution until this message is removed.

These instructions cover setting up WeBWorK 2.15 using the WeBWorK 2.15 Ubuntu Server 20.04 LTS Amazon Machine Image.

This "server" version contains everything you need to run a WeBWorK server (e.g. WeBWorK, Ubuntu Server, Apache2, MySQL, R server, lighttpd, log rotation, etc.) installed and configured.

Setting up the WeBWorK 2.15 Ubuntu Server 20.04 LTS Amazon Machine Image

Overview

After setting up the WeBWorK 2.15 Ubuntu Server 20.04 LTS Amazon Machine Image, you will have a full fledged Ubuntu Server 20.04 LTS system with WeBWorK 2.15, Apache2, MySQL, R server, lighttpd, log rotation, etc. installed and configured.

It is imperative that you CHANGE THE PASSWORDS for the OS user wwadmin (who owns most WeBWorK files), for the MySQL user webworkWrite who has access to MySQL, for the WeBWorK user admin who has admin privileges and for the WeBWorK user profa who has professor privileges (see below). Finally you should set up SSL (https) access to WeBWorK if students will be using your server.

There are more detailed instructions for Ubuntu Server 20.04 and WeBWorK 2.15 at Installation Manual for 2.15 on Ubuntu 20.04 Server. The AMI (Amazon Machine Image) was built following those instructions.

Find the AMI image

Search for WeBWorK 2.15 on Ubuntu Server 20.04 LTS

Configure the WeBWorK AMI Image

Select the WeBWorK 2.15 on Ubuntu Server 20.04 LTS AMI and hit Launch

Choose an Instance Type

Information on ec2 instance types can be found at https://aws.amazon.com/ec2/instance-types/

The WeBWorK AMI was built from a t2.micro ec2 instance (which is free tier eligible) having the following resources:

  • 20 GB disk drive of which about 6 GB is used
  • 1 GB memory
  • 1 (virtual) cpu

The above resources are very minimal. These resources are OK for testing but it is easy to overwhelm the machine even with a single user. This may happen e.g. if you want to simultaneously display many problems in the Library Browser. If this happens your options are to wait until the server recovers or reboot the server.

The Mathematical Association of America (MAA) courses1 server (https://courses1.webwork.maa.org/webwork2) is a t2.2xlarge ec2 instance having the following resources:

  • 70 GB disk drive
  • 32 GB memory
  • 8 (virtual) cpu's

The MAA courses1 server is hosting over 600 courses of which around 150 were active in June, 2020.

Most likely the resources required for you server will fall within the range from t2.micro to t2.2xlarge. You can always change the resources available to an instance but for this you will have to stop the instance. After restarting the instance will have a new ip address which means you will have to change the network setup (see The WeBWorK URL below). For this reason it is best to start will reasonable resources.

Configure Instance Details

Add Storage

You can change the amount of disk space

Also make sure that Delete on Termination is unchecked. Otherwise when you stop you instance, your root volume /dev/sda1 will be deleted and this contains all changes you or your students may have made. Note that rebooting your server does not do this but stopping it (e.g. to increase memory or other resources) will.

Add Tags

Read about Tags and add some if you want (e.g. name the instance)

Configure Security Group

You can use the default security group or create a new one. You also should create inbound rules so that you and others can communicate with your server instance. SSH is already set up but the source 0.0.0.0/0 means, as the warring states: "Rules with source of 0.0.0.0/0 allow all IP addresses to access your instance." You can restrict this to a specific workstation (e.g. 98.12.176.149/32) or a range (e.g.98.12.176.0/24).

SSH	            TCP	           22	          98.12.176.149/32

You should also allow HTTP (port 80) and Lighttpd (port 8080). Initially for testing you may want to restrict these but for a production machine you would want to allow from anywhere, i.e. 0.0.0.0/0

HTTP	            TCP	            80	           0.0.0.0/0	
Custom TCP	    TCP	            8080	   0.0.0.0/0

Launch Your Server

Create a new key pair or use an existing one. Download and save the pem file (e.g. WWsecretkey.pem).

Now Launch you server.

On you EC2 Dashboard (EC2 Management Console), find the IPv4 Public IP address, say 18.220.210.191. Will use this in our examples. Obviously you should substitute your own.

Accessing Your Server from a Terminal Emulator on your Host

You can login to your server using SSH (non secure telnet and FTP are not allowed but secure SSH and SFTP are) using your favourite terminal emulator program.

If you use a terminal emulator like MobaXterm use the Advanced SSH Settings to use the WWsecretkey.pem file as your private key and connect to 18.220.210.191 and login as ubuntu (no password required). Other terminal emulators (Putty, iTerm2, etc) will be similar.

If you are using ssh in a terminal window, use the command

ssh -i WWsecretkey.pem ubuntu@18.220.210.191

(you may have to provide the path to the WWsecretkey.pem file). Note that the permission on the WWsecretkey.pem file is required to be set so that the file is not readable by others. You need something like

chmod 600 WWsecretkey.pem

If you are using a bash shell running on Ubuntu under Windows 10, you may find it impossible to change the permission of WWsecretkey.pem. In that case copy WWsecretkey.pem to your home directory and change the permission there. From the directory containing WWsecretkey.pem

cp WWsecretkey.pem ~/
cd 
chmod 600 WWsecretkey.pem
ssh -i WWsecretkey.pem ubuntu@18.220.210.191

Users on your system

There are two users who can login to the system: ubuntu and wwadmin

ubuntu

ubuntu is the "system" user who has sudo privileges. You probably always want to initially log in as ubuntu.

Running commands as root

By default your Ubuntu server has no password set for the root user. To gain root access you have to use the sudo command while logged in as ubuntu.

To run commands as root use

$ sudo <command>

A log of all sudo commands is kept in /var/log/auth.log .

You can also use sudo to become root and get the root prompt #. To do this run

$ sudo su
#

When you want to exit the root prompt and return to being the regular user ubuntu, do the following

# exit
exit
$

wwadmin

wwadmin is the "WeBWorK" administrator user who owns most of the WeBWorK system files. For example if you want to edit some WeBWorK file, you should use the su (switch user) command to become wwadmin. The password for wwadmin is "wwadmin" so the command is:

$ su wwadmin
Password: wwadmin
$

After you have finished whatever you have to do as wwadmin, you can return to being the ubuntu user by

$exit
exit
$

wwadmin is not in the sudo group so if you want to use sudo, you have to be ubuntu.

Also you should change the password for wwadmin to something much more secure than "wwadmin" (see Passwords).

Set the Timezone for your server

To find out what timezone your server is set to run the command

$ timedatectl

and you will probably see (in the summer)

...
Time zone: America/New_York (EDT, -0400)
...

which may not be where you live. The timezone naming convention uses a “Region/City” format and to find the correct one for your location run the command

$  timedatectl list-timezones

Look through the list and find your timezone, e.g. "America/Los_Angeles". Then set the timezone (you have to be root), e.g.

$ sudo timedatectl set-timezone America/Los_Angeles

and then

$ timedatectl

to check it was set correctly.

Checking for and installing hotfixes

Follow the instructions at Checking for and Installing Hotfixes in the Installation Manual for 2.15 on Ubuntu 20.04 Server.

WeBWorK Configuration

The WeBWorK URL

We need a WeBWorK URL both to

  1. configure WeBWorK by editing the localOverrides.conf file
  2. to give to students and professors so that they can access WeBWorK

For this we can use your servers public ip address (e.g. 18.220.210.191) or public URL address (e.g. ec2-18-220-210-191.us-east-2.compute.amazonaws.com) but besides being hard to remember this is really not a good idea for the following reason. These public addresses are only "semi-permanent". As long as your server instance is running they will remain fixed and will also remain fixed if you reboot your instance. However, if you stop your instance for any reason (e.g. to increase the resources it has) the public addresses will disappear and when you restart your server, it will have new and different public addresses. Then you will have to edit the localOverrides.conf file and tell all your users they need to use a new URL to access WeBWorK.

It is much better to use a permanent URL (something like webwork.yourschool.edu) and direct that to the public ip address of your instance (18.220.210.191 in our example). Then if your ever have to stop and restart your AWS instance, all you have to do is to redirect webwork.yourschool.edu URL to the new public ip address. In my experience such changes propagate through the name servers in minutes.

If for whatever reason you do not want to use a university URL, you can use Google Domains (https://domains.google/) or a similar provider to get and manage your own URL.

The WeBWorK .conf files

Most WeBWorK configuration is done in the files /opt/webwork/webwork2/conf/site.conf and /opt/webwork/webwork2/conf/localOverrides.conf. These files provide system-wide configuration settings, and defaults for course settings. Any setting in these files can be overridden in the course.conf file for a particular course. To override a setting for a course, just put the new setting (using the same syntax as is in localOverrides.conf) in the course.conf file. An instructor can only edit the course.conf file herself (for her own course) if she has "admin" privilege which by default professors do not have. But most things instructors may want to customize and many others (language, timezone, permissions, display modes, email, ...) can be set using the Course Configuration page from within the course and such setting override those in the configuration files.

Usually the "admin" user is added as an admin in all new courses and she can grant "admin" privileges to anyone (but she should be very careful in doing this).

Actually there are three main configuration files, site.conf, defaults.config and localOverrides.conf. The reason there are three configuration files is to make upgrading WeBWorK easier.

  • site.conf: This file contains global variables which are required for basic configuration. It will not be overridden when you update WeBWorK but its distribution version, site.conf.dist will be.
  • defaults.config: This file contains initial settings for many customizable options in WeBWorK. Do not edit defaults.config. It will be overridden next time you upgrade.
  • localOverrides.conf This is where you should add all local customizations. It will not be overridden when you update WeBWorK but its distribution version, localOverrides.conf.dist will be.

It is important to remember that any time you edit WeBWorK's configuration files, you have the restart Apache2 for the changes to take effect.

There are several options that must be set for WeBWorK to work with your system. The rest of the file consists of customization options.

Edit the site.conf file

Now backup and edit site.conf

$ su wwadmin
Password: wwadmin
$ cd /opt/webwork/webwork2/conf
$ cp site.conf site.conf.bak1


The $server_root_url is set as

 $server_root_url   = 'http://localhost';

which should be fine.

WeBWorK uses the DateTime module. DateTime is supposed to be able to determine the local timezone itself without you having to enter it but this often fails so it is best to just set it here. For is a list of timezones recognized by DateTime run the command

timedatectl list-timezones

These timezones are more refined than standard time zone usage in that they include switches to daylight savings time (e.g. some parts of a time zone may make the switch and others may not). For example if your server is in the eastern US, on the list you will see America/New_York and you should enter $siteDefaults{timezone} = "America/New_York"; which is the default. Read the documentation in this section of the the site.conf file for more information on selecting time zones and formatting dates.

Now edit site.conf

$ nano site.conf

Search for $siteDefaults{timezone} and enter your local timezone if it is not correct.

Here is some information on email although you might want to hold off on this until you check that your server is functioning well.

WeBWorK sends mail in three instances. The PG system sends mail to report answers to questionnaires and free-response problems. The mail merge module is used to send mail to course participants, i.e. to report scores. The feedback module allows participants to send mail to course instructors.

To send mail, WeBWorK needs the address of an SMTP server. Normally you will use the address of your school's SMTP server. When connecting to the SMTP server, WeBWorK must also send an email address representing the sender of the email (this has nothing to do with the From address on the mail message). Edit the lines

$mail{smtpServer} = ;  # e.g. 'mail.yourschool.edu' or 'localhost'
$mail{smtpSender} = ;  # e.g.  'webwork@yourserver.yourschool.edu'

entering the appropriate information. Be sure to use single quotes and NOT double quotes around email addresses otherwise Perl will treat @ as an array variable.

If you do not use your school's SMTP server, the following documentation may be helpful:

https://docs.aws.amazon.com/ses/latest/DeveloperGuide/send-email-smtp.html

https://aws.amazon.com/premiumsupport/knowledge-center/ec2-port-25-throttle/

https://docs.aws.amazon.com/ses/latest/DeveloperGuide/send-email-smtp-software-package.html


Then save the file and Quit.

The defaults.config file

If you want WeBWorK questionnaires or similar things from different courses to be mailed to a central person or persons (e.g. the WeBWorK administrator), in defaults.config, you will see the lines

$mail{allowedRecipients}     = [
   #'prof1@yourserver.yourdomain.edu',
   #'prof2@yourserver.yourdomain.edu',
];

But we are not supposed to edit the defaults.config file, so if we want to do this, we will copy this to localOverrides.conf and edit it appropriately. Note that we should move this setting to the site.conf file.

Edit the localOverrides.conf file

Now backup and edit localOverrides.conf (we already have two backups)

$ cd /opt/webwork/webwork2/conf
$ cp localOverrides.conf localOverrides.conf.bak3
$ nano localOverrides.conf

We have to replace all occurrences of aws.apizer.org by your the new URL (webwork.yourschool.edu in our example above). You can do this one by one or by a global search and replace. To use global search and replace enter the command:

^ \
Search (to replace) [...]:aws.apizer.org
Replace with:webwork.youryourschool.edu
A

where of course replace webwork.yourschool.edu by your actual URL.

As we said above, if you want WeBWorK questionnaires or similar things from different courses to be mailed to a central person or persons (e.g. the WeBWorK administrator), in localoverrides.config, add and then edit the lines

$mail{allowedRecipients}     = [
   #'prof1@yourserver.yourdomain.edu',
   #'prof2@yourserver.yourdomain.edu',
];

Of course you have to remove the comment character #.

Then save the file and Quit.

Now restart apache so that our changes to the conf files takes effect.

$ sudo apache2ctl restart

Set up WeBWorK to use SSL

This step configures apache so that access to WeBWorK will be through an encrypted Secure Sockets Layer (SSL) with an https: URL. It is optional but you should certainly do this if students will be using your server. However, I would hold off on this until you have tested that everything is working properly.

Follow the instructions at Implement Optional C (SSL) in the Installation Manual for 2.15 on Ubuntu 20.04 Server.

Finish up

Once access to your WeBWorK server is set up (as it should be now), if all you want to do is test out WeBWorK yourself without any other users, you are all set at this point but please read the rest of these instructions so that you understand how insecure your WeBWorK server is right now.

Test that Things are Working Properly

Connect to http://webwork.yourschool.edu/webwork2 where of course you should use your actual URL. We will test out a few important parts of WeBWorK. If you run into problems, you should look at the Apache error log which is located at /var/log/apache2/error.log. And you should look at Test that Things are Working Properly in the Installation Manual for 2.15 on Ubuntu 20.04 Server for help.

You should see the WeBWorK Welcome page with "Course Administration" and "myTestCourse" listed. At some point you may want to "hide" them so that they are not listed on the Welcome page (more on this later).

Click on "myTestCourse" and login with login name "profa" and password "profa". At this point you are a regular professor. There is also an administrator "admin", a regular student "jsmith" and several guest or practice users (who don't require a password but can view problems and "check" answers without them being "submitted" for credit). More on these below.

Now click on Homework Sets on the Main Menu and click on Demo. Then look at the problems. Mathematical equations should be typeset. Continue looking at problems to see if everything is working properly. Look through the problems in the other sets.

Next click on Problem List to bring back the Problem List Page and click on Download PDF .... The page is a little complicated because you are a professor so you see the professor view (students see a very simple page) but you can just scroll to the bottom and click on Generate hardcopy for selected users and selected sets.

Look through the problems in the other sets.

Now test the Library Browser. Note when using the Library Browser the default is to view 20 problems at once. If you are using the t2.micro ec2 instance level, this may overwhelm the server. You can display fewer problems and e.g. use the "top" command to check the load on the server.

If "top" shows a high load average and/or shows the kswapd0 process taking a large percentage of cpu then your system is getting overwhelmed. In particular kswapd0 manages virtual memory and may be having issues due to moving processes to SWAP too frequently, causing cpu spikes and decreased system performance. The solution is to allocate more memory to your instance. If your server gets hopelessly bogged down, you can try to wait it out or just reboot.

Click on Library Browser on the Main Menu. Click Open Problem Library (actually it should already be selected so it will be greyed out) and select a Subject, Chapter and Section and then hit View Problems. The first 20 of your selected problems will be displayed.

Next test that WeBWorK problems using R run properly. You are already in the Library Browser. Select "Statistics" as Subject, "Bayesian inference" as Chapter and "Posterior distribution" as Section and then hit View Problems. If the problems display with no error messages, all should be well. To be totally sure, click on the "eye" (Try it) in the upper right corner and test the problem. If there are no error messages, congratulate yourself. Everything works.

If you are new to WeBWorK or even if you are a pro, you should probably log in as that student to see what the student interface looks like. It's much simpler than the professor or admin interfaces. Login with login name "jsmith" and password "jsmith". The "admin" view is very similar to the "prof" view but you have the ability to change things about the course that mere professors do not have. Finally you can click on "Guest Login" and see what that looks like.

Passwords

It is IMPERATIVE that you CHANGE THE PASSWORD for the OS user wwadmin (who has ownership of the WeBWorK files). Otherwise anyone can connect to your server and pretty easily gain access to the WeBWorK files. Also it is IMPERATIVE that you CHANGE THE PASSWORD for the MySQL user webworkWrite who has login privileges to MySQL. Otherwise anyone can connect to MySQL server and pretty easily gain access to the WeBWorK database. Finally it is IMPERATIVE that you CHANGE THE PASSWORD for the WeBWorK user admin who has admin privileges both in the admin course and in the myTestCourse and for the WeBWorK user profa who has professor privileges in the myTestCourse. Otherwise anyone can connect to WeBWorK server and pretty easily gain access and do anything they want.

Change the password for wwadmin

$su wwadmin
Password: wwadmin
$ passwd
Changing passwd for wwadmin:
(current) UNIX password: wwadmin
Enter new UNIX password: <new wwadmin password> 
Retype new UNIX password: <new wwadmin password>
passwd: password update successfully
$exit
exit
$ 

Do not forget the <new wwadmin password> that you just entered. Below when we refer to <wwadmin password>, we mean the new <wwadmin password> (<new wwadmin password>).

Change the password for webworkWrite

Now we change the passwords for the MySQL user webworkWrite. First we edit site.conf.

$su wwadmin
Password: wwadmin
$ cd /opt/webwork/webwork2/conf
$ nano site.conf

Search for $database_password = "wwadmin"; and replace this by
$database_password = "database_password"; where of course you should replace 'database_password' with your own password. We refer to this password as <database_password>. Remember it as we will need it shortly. Then save the file and Quit.

Then restart Apache so the changes take effect.

$ exit
exit
$ sudo apache2ctl graceful

and start MySQL

$ sudo mysql

You should see

Welcome to the MySQL monitor ...
mysql>

Now lets check the MySQL users.

mysql> SELECT user,authentication_string,plugin,host FROM mysql.user;

You will see a table with six users (debian-sys-maint, mysql.infoschema, mysql.session, mysql.sys, root and webworkWrite). You should see that five users have a valid password (which will be displayed in encrypted form) and root is authenticated by a socket.

Now we will change the password for the webworkWrite User

mysql> ALTER USER 'webworkWrite'@'localhost' IDENTIFIED BY '<database_password>';

where of course you should replace <database_password> by whatever you used above (use the single quotes but no angle braces). Then

mysql> FLUSH PRIVILEGES;
use your up arrow key to run the command
mysql> SELECT Host, User, authentication_string FROM mysql.user;

and you should see that webworkWrite has a new passwords (which will be displayed in encrypted form).

Then exit MySQL

mysql> exit
Bye
$

If you want to check that you set the password correctly, do the following:

mysql -u webworkWrite -p -h127.0.0.1 --protocol=tcp
Enter password: <database_password>

and you should see

Welcome to the MySQL monitor ...
mysql>

Now exit

mysql> exit
Bye
$

Finally a note on the MySQL root password. In Ubuntu systems running MySQL 5.7 (and later versions), the MySQL root user is set to authenticate using the auth_socket plugin by default rather than with a password. However in securing MySQL (see Installation Manual for 2.15 on Ubuntu 20.04 Server#MySQL Security and Performance Issues) we had to set a password for the MySQL root user and that password was set to "wwadmin" even though it is not used. If you ever change how the MySQL root user is authenticated (you shouldn't!!), remember this.

Change the password for admin

Change the passwords for the WeBWorK user admin in two courses. Login to both the WeBWorK admin course (http://.../webwork2/admin) and myTestCourse (http://.../webwork2/myTestCourse) with Username "admin" and Password "admin". Then change the passwords from "admin" to something more secure. Note that in WeBWorK to change the password of the user you are logged in as, select "User Settings" in the "MAIN MENU". Or you can login as "profa" and use the "Classlist Editor" to change the password.

Change the password for profa

Change the passwords for the WeBWorK user profa. Login to myTestCourse (http://.../webwork2/myTestCourse) with Username "profa" and Password "profa". Then change the passwords from "profa" to something more secure. Or you can login as "admin" and use the "Classlist Editor" to change the password.

Change the password for jsmith

Change the passwords for the WeBWorK user jsmith if you want. jsmith is just a regular student so she can't do any real damage but you may still want to change the password. Login to myTestCourse (http://.../webwork2/myTestCourse) with Username "jsmith" and Password "jsmith". Then change the passwords from "jsmith" to something more secure. Or you can login as "admin" or "profa" and use the "Classlist Editor" to change the password.

More House Keeping

Hide the admin and myTestCourse courses

Log out of myTestCourse if you are logged in and go to the WeBWorK Welcome page. Click on Course Administration and login as admin with the new admin password you set for the admin course. Select "Hide Inactive Courses" and select the courses you want to hide and hit "Hide Courses". If you go back to the WeBWorK Welcome page, you will see no courses listed. You can still access these courses directly by

http://webwork.yourschool.edu/webwork2/admin 
http://webwork.yourschool.edu/webwork2/mytestcourse 

where of course you should use your actual URL.

Adjust Apache's configuration according to your server's memory

Look at Edit mpm_prefork.conf in the Installation Manual for 2.15 on Ubuntu 20.04 Server and adjust "MaxRequestWorkers" according to the rule of thumb given there.

Set up access to Apache's server-info and servo-status

This isn't really necessary but you should look at the info.conf and status.conf section in Installation Manual for 2.15 on Ubuntu 20.04 Server. Actually this is something that you should do after connecting your WeBWorK server to the outside world.

Increase disk space

This is a two part process. The first step is to use your virtualization software to expand the disk capacity. How to do this obviously depends on your specific virtualization software. You will find information on this in Specific Virtual Environments below. The second step is to repartition the disk and expand the file system. Let us assume you have completed the first step and expanded the disk capacity from it's initial 20 GB to 30GB although in practice you will probably want to make it larger. First enter

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
...
/dev/sda2        19G   11G  7.3G  59% /
...

to see how much disk space we have initially. Now run parted as root:

$ sudo parted

and you will see something like

GNU Parted 3.3
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) 

Now enter the "print" command

(parted) print
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sda: 21.5GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:   

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  2097kB  1049kB                     bios_grub
 2      2097kB  20.0GB  20.0GB  ext4

(parted)

We need to know the number of the partition we want to resize. We can see it is 2 from the above. Now enter the "resizepart" command

(parted) resizepart
Partition number? 2
Warning: Partition /dev/sda2 is being used. Are you sure you want to continue?
Yes/No? Yes
End?  [20GB]? 30GB
(parted)

Now enter the "print" command again

(parted) print
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sda: 31.5GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  2097kB  1049kB                     bios_grub
 2      2097kB  30.0GB  30.0GB  ext4

(parted)

Notice we now have a 30 GB disk. Now quit parted.

(parted) quit
Information: You may need to update /etc/fstab.

Now we resize the file system. The above information tells us that we are working on partition 2 on /dev/sda, so we use /dev/sda2 in the command below

$  sudo resize2fs /dev/sda2

resize2fs 1.45.5 (07-Jan-2020)
Filesystem at /dev/sda2 is mounted on /; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 3
The filesystem on /dev/sda2 is now 4882300 (4k) blocks long.

and run df -h and we should see something like

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
...
/dev/sda2        29G  11G  18G  38% /
...

indicating that we now a lot more space on our disk. Yea!

Checking for and Installing Hotfixes

The following commands show you how to check for and install bug fixes. Important Note: These commands check and retrieve the master branch which gives the latest stable release of the software package (webwork2, pg, etc.) with bug fixes. If a stable release newer than 2.15 exists for webwork2 and/or pg, that will be checked and retrieved which is probably not what you want. Please check before updating. The best way to do that is to look at https://github.com/openwebwork/webwork2/blob/master/VERSION and https://github.com/openwebwork/pg/blob/master/VERSION.

To check if there are bug fixes, do the following.

Updating the webwork2 code

First we check for updates to the webwork2 code:

cd /opt/webwork/webwork2/
git remote show origin

This will print several lines of data, but the last line will tell you if your copy is up to date or out of date. If it is out of date, run

git pull origin

and restart apache2.

Updating the pg code

Now check for updates to the pg code:

cd /opt/webwork/pg/
git remote show origin

This will print several lines of data, but the last line will tell you if your copy is up to date or out of date. If it is out of date, run

git pull origin

and restart apache2.

Restart apache2

Important: After updating either webwork2 or pg, you have to restart apache2

$ sudo apache2ctl restart
password:<wwadmin password>

Updating the OPL

The following assumes you have already installed the OPL. For that see #Install the Open Problem Library below. Now check for updates to the Open Problem Library:

cd /opt/webwork/libraries/webwork-open-problem-library
git remote show origin

This will print several lines of data, but the last line will tell you if your copy is up to date or out of date. If it is out of date, run

git pull origin

Then rerun the OPL-update script. Updating the OPL is pretty much risk free since changes usually involve only a relatively small number of individual problems and the vast majority of problems remain unchanged. Updating the OPL does not require restarting apache2.

$ OPL-update


File and Directory Locations and System Information

This installation of WeBWorK and Ubuntu follows the instructions given in Installation Manual for 2.15 on Ubuntu 20.04 Server. You can look there to find the locations of the WeBWorK files. All optional configurations (A-E) are implemented except that

  1. Optional A is implemented with the wwtmp directory set up as a separate directory but not as a separate partition and
  2. Optional C is not implemented. Optional C configures Apache (and optionally lighttpd) so that access to WeBWorK will be through an encrypted connection (TLS/SSL) with an https: URL. This has to be done locally and you may have already implemented this.

All system files are in their standard Ubuntu locations. The Ubuntu installation is identical to that obtained from the AMI image "Ubuntu 20.04 LTS - Focal" provided by Canonical Group, Ltd. (see https://aws.amazon.com/marketplace)

Consult Category:Administrators for other WeBWorK documentation for system administrators.

Your server

After launching your WeBWorK instance will be identical to a system created by following the instructions Installation Manual for 2.15 on Ubuntu 20.04 Server with all Optional Configurations A-E implemented except that

  1. The Ubuntu Server 20.04 LTS image is from the "Ubuntu 20.04 LTS - Focal" AMI provided by Canonical Group, Ltd. (see https://aws.amazon.com/marketplace)
  2. snapd has been removed (see snapd below)
  3. Optional C (SSL) is not implemented
  4. The PGbasicmacros.pl file has been slightly changed (see PGbasicmacros.pl below)

The implementation of Optional C (SSL) should be done locally after you have checked that everything is working (see below).

You should read through the instructions Installation Manual for 2.15 on Ubuntu 20.04 Server in order to understand how your server has been set up. Especially look at Terminal Window Notation and Use in the Installation Manual for 2.15 on Ubuntu 20.04 Server to understand the notation we use in these instructions.

Known Issues

Here are the known issues with this release.

PGbasicmacros.pl

Displaying certain symbols (e.g. {, },<,>,≤, ≥) in the text (not in Math Mode) of a WeBWorK problem fails. An example is Problem 1 in Set 0 in "myTestCourse" (see Test that Things are Working Properly below). For information on this see https://github.com/openwebwork/pg/issues/473.

To fix this the PGbasicmacros.pl file (in the directory /opt/webwork/pg/macros) has been slightly changed. The original file is PGbasicmacros.pl.bak1 in the same directory. This may or may not be addressed in a WeBWorK 15 hotfix (see Checking for and Installing Hotfixes).

UTF-8 support

WW 2.15 has some "known issues" with the UTF-8 support that arise in some WeBWorK problems. These issues are discussed in a forum discussion at: https://webwork.maa.org/moodle/mod/forum/discuss.php?d=4795. The discussion there lists pull requests by Nathan Wallach and Davide Cervone that address these issues. If you write or use WeBWorK problems that have issues with UTF-8 characters, look at that discussion. Again these issues may or may not be addressed in a WeBWorK 15 hotfix (see Checking for and Installing Hotfixes).

snapd

In our t2.micro instance, snapd was using a large amount of resources, so we removed it

$ sudo systemctl stop snapd
$ sudo apt purge snapd
$ sudo apt autoremove


-- Main.ArnoldPizer - 10 May 2020