Tools of the trade: Mac Apps

Today I want to call out a couple of Mac apps that I personally have found to be a great help to me as a systems admin and builder. These are all simple things that help me get work done.

Termius

Termius

Part of the reason I switched from Windows to Mac when I took my job was to have easier access to a bash terminal. But after a few weeks, I found that using the built in Mac Terminal app wasn’t very efficient for me. I had something like a dozen production and development servers to access on a regular basis, plus a growing amount of resources in AWS, and manually typing in hostnames, users, passwords, and tracking keys seemed unnecessarily burdensome. Before long I found Termius, which is a great SSH manager. Now I add my host information into Termius and can login into whatever server I need in seconds.

It can be used on a laptop for free but my boss was kind enough to purchase a license for me so I have extra features and can sync my credentials to multiple devices. That’s cool because Termius works just about anywhere, including my iPad and iPhone. The Mac app looks great, performs well, and also includes an SFTP client and the ability to save “snippets” so you can save and re-use tricky or frequent commands.

Cost: Freemium (60 USD per year)

Pro tip: Organize hosts into Groups and set a default color scheme. I use the classic black and green for my dev servers and a light color scheme on production so I can tell at a glance what environment I’m in.

LastPass

LastPass

Let’s face it, passwords suck. But until biometrics or physical tokens or something else totally take over we’re stuck with them. I had been using this app for awhile personally and my team invested in LastPass about 6 months ago. It has made sharing credentials to access some of our tools much easier (and safer.)

Most people probably use LastPass exclusively as a browser plugin that can auto-fill passwords. But it also comes with a pretty nice Mac app if you want to get a bit more in-depth. Beyond username/passwords, there are templates to store lots of useful things server info, private keys, account numbers, credit cards. and billing information. 

Cost: Freemium (2 USD per user per month)

Pro tip: When the Mac app is running, you can invoke a quick search of your vault with CMD-Shift-L . From the search results there are buttons to quickly copy usernames or passwords to your clipboard.

Amphetamine

The life of systems administration sometimes involves a lot of waiting around waiting for a process to finish. Sometimes, you need your laptop to stay awake even if you’d rather step away. Amphetamine is an app that does just that. Just turn it on and your Mac will stay awake without needing to futz with power saving settings. 

Cost: Free!

Pro tip: You can choose criteria to keep your Mac awake: while a certain app is running, for a certain amount of time, or indefinitely. Keep this app on, then lock your screen (CTRL-SHIFT-Power button) to let a process run while you go take a coffee break//walk/nap.

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Gushing Over Git

When I started working in sysadmin/ops land, I knew that version control would be important, and knew a little bit about it. I had used Git in a very basic way while playing around with some amateur coding projects. I knew how to initialize a repo, see which files were tracked, and stage and commit changes.  But I didn’t quite appreciate how crucial a thorough understanding of Git would be to really be effective in maintaining and deploying code in a systems context – with thousands of users depending on availability of a server that needs to be patched, updated, etc safely, securely, and on-schedule. It didn’t take long before I was dedicating as much time as possible to mastering Git. I even created a “Git” section on my OneNote notebook, which is a big deal if you know me.

I knew I needed to learn a lot in a hurry. Thankfully, not only is Git Open Source software with thorough documentation – there is a real open community around git. A great example of this is the Pro Git textbook. This is a fantastic OER (open education resource). The book can be viewed online or downloaded in an ebook format for free. In my case, I downloaded the .mobi Kindle format and used the “Send to Kindle” option to add the ebook to my Kindle library. This allowed me to read the book with variable fonts and text sizes, and to highlight and make notes. There are also tons of good forum spaces for discussing git and asking questions (or more likely finding an answer that has already been given), from Stack Overflow forums specifically for GitHub.

Another virtue of git is that by its nature, it allows you to experiment and play. I cloned a repo of my institution’s production Moodle code into my own safe practice space, knowing that I could try things out and was perfectly safe as long as I didn’t push any commits back. And even if I did somehow end up with bad code, you can always reset back to a working commit. This allowed me to work on git skills and have a Moodle directory to explore and mess-up in a consequence free environment.

The git skills I’ve built have already paid off – aside from being crucial to any sane workflow for updating Moodle or WordPress sites, git has already saved me from crashing a site at least once. I got a bit sloppy on a dev WordPress site and did something to the wp-config PHP file that crashed the site. Yikes! It could have been anything from a missing semi-colon to a misspelled word. Hard to say, but the site was totally dead. Instead of spending a lot of valuable time poring over the file to find the typo, I executed a simple command:

sudo git checkout wp-config.php

The one area of consternation I’ve had with Git has been with submodules. The previous Moodle admin at my school set-up a submodule system to manage all of the various plugins we run (50 or so at last count). In theory this should make managing a suite of plugins easier, but in practice I’ve struggled with submodules, at least in terms of using them at all efficiently, as they make the git process a bit more complicated conceptually. However I am starting to get the hang of submodules now and and getting clarity on how they function in relation to the “superproject” in which they reside. This article from Catalyst, The Git submodule: misunderstood beast or remorseless slavering monster?  was especially helpful for me.

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It’s All About the Data

This is going to sound stupid, but…One thing I didn’t really think about enough prior to starting my current job is just how much working with data is involved. Yes, I know. Information systems. It’s kind of all about data. But when I imagined what this job would entail, I thought a lot about building things, about creating systems that support and spark teaching and learning. The reams and reams of data that go along for the – names, email addresses, course CRNs, logs, files, etc – just didn’t seem that sexy to me.

But after a few months of being a sysadmin, I’m thinking about data more and more. There are the obvious things: am I doing enough to keep data safe in the age of constant breaches? Are we thinking about giving users control of their data in any meaningful way in light of evolving views about digital privacy? These are big questions. But in the day to day, I’m just working with like, rows and rows and rows.

It turns out, people have questions they want answered about the digital systems that play such an important role in our schools. These are all questions I’ve answered in the last month:

Which instructors used the accessible Moodle theme we provided in their courses?

I accidentally deleted a quiz, is there any way to get the grades each student in my class got on it?

Can you tell me who at the University has not yet completed this mandatory training?

How many people logged into Moodle on the first day of classes?

Here is the CRN numbers of 50 courses – can you get me the course full name, id number, and the instructor of record?

So what have I learned?

Sometimes this data is readily available within an application itself. For example in the recent versions of Moodle each course has a very powerful completion tracking and activity tracking report built-in. It is also be possible to extend this functionality with plugins.

Reports or logs can also generally be exported into a .csv or spreadsheet format. I was already pretty proficient with Excel but I’ve upped my game in the last few months just due to the amount of time I’ve spent in spreadsheets. (I don’t think I’ve opened PowerPoint in that time, I’ve kind of flip-flopped in that regard. Less presenting polished data and more churning through raw data).

In addition to a sheets tool, a good plain-text editor is your friend when data needs to be manipulated to be useful. I’ve been using VS Code and find it really useful for manipulating text, especially the ability to find and replace with a regex expression. This is incredibly handy when you have a comma separated list but it just has to have each item on a new-line to import wherever it is you need it to go.

If built-in reports or exported info isn’t cutting it, I’ve been going straight to the source itself: typically the Moodle database accessed by PHPMyAdmin. This lets me run SQL queries in a pretty friendly GUI environment and export the results. I’ve found that simple SQL itself is relatively easy to write – it’s understanding the complex structure of a huge relational database, how the tables need to be joined, and thinking through the links between tables that takes a bit of time. But, I am getting faster at this process – I find sketching the query out and making kind of a map of the relevant tables and fields helpful – and this is what has allowed me to do things like recover the grades of a deleted quiz or return a list of instructors who have used a certain theme.

Sketching out a SQL query
Sketching out a SQL query

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Patch Notes: The Case of the Mysterious Crashing Server

I’ve been kicking a few ideas around, thinking about what topics or experiences I wanted to write about to chronicle my journey into systems administration/architecture. This week I had the fortunate misfortune to to come across the perfect situation for the first entry in this blog series when I received an email from one of the math professors at UP about our WeBWork server.

A bit of background on WebWork: it’s an open source program for delivering math homework via the web. We’ve run it at UP for a number of years, and recently migrated to AWS , using a single instance running Ubuntu.

Back to our emailing professor. She had been using the system over the holiday break and noticed intermittent lock-ups. She could use the site normally for about half an hour before things went sideways and it became unresponsive; if she waited a few hours and came back it would be working again, but only for about 30 minutes at a time.

After getting the email I checked the server and yeah, it was totally unresponsive via the web and SSH. Time for a hard reboot via the AWS console. After rebooting everything seemed fine but before long the prof let me know she was still experiencing the same issues. This time I was able to SSH in before things went totally haywire – but trying to execute any commands returned an error:

-bash: fork: Cannot allocate memory

Aha! A clue. I rebooted again and downloaded htop:

sudo apt-get install htop

htop is a CLI program for monitoring system usage – including memory. I hadn’t used it before, so I took advantage of the Lynda.com account I have through work and watched a good htop tutorial video to get a feel for it. When WebWork was in use, I could see via htop that there were some processes owned by the Apache server (www-data) that were eating up all of the available memory, of which we only had a paltry 4GB (I suspect that the original sysadmin who built the server intended to use an auto-scaling group that would spin-up additional resources on-demand, but was never able to get this working correctly).

A bit of research turned up lots of forum posts that discussed WebWork’s nasty habit of eating up system memory and failing to give it back, which over time can use up all the available RAM and result in crashes – some useful threads:

Through these posts, I learned about the Apache Max RequestWorkers and MaxConnectionsPerChild parameters. These control how many processes the server can spawn before shutting the oldest/most bloated ones down and can be tweaked to keep WebWork from running too many memory-obliterating tasks at once. It’s a balancing act, though: allow too few simultaneous requests, and unnecessary lag is introduced as Apache is forced to create new processes constantly while memory sits unutilized. A quick visit to the appropriate Apache config file at /etc/apache2/mods-available/mpm_prefork.conf confirmed that the server was still at the default setting of 150 Request Workers and unlimited child connections per requests (0 = unlimited in this case).


StartServers             5 
MinSpareServers          5 
MaxSpareServers          10 
MaxRequestWorkers        150 
MaxConnectionsPerChild   0

A bit more research turned up the install guide for WebWork on Ubuntu and “a rough rule of thumb” of 5 MaxRequestWorkers per 1 GB of memory and a MaxConnectionsPerChild value of 50.

This gave me the formula to determine optimal Apache settings but I wanted to increase the system RAM as 4GB still seemed likely to be insufficient for any heavy use. This was easy to do in AWS as the WebWork instance was a simple single Elastic Block Store (EBS) backed EC2 Amazon Machine Image (AMI).

In the EC2 AWS console:

  • Take a snapshot of the root volume attached to the instance (just in case)
  • Instance state -> Stop
  • Actions -> Change instance type (in my case I changed from t2.medium with 4GB RAM to a t2.large with 8GB RAM)
  • Instance state -> restart

I logged back in and tuned the Apache server for 8GB of RAM with the following settings in the mpm_prefork.conf file (8GB X 5 = 40):

StartServers             5 
MinSpareServers          3 
MaxSpareServers          5 
MaxRequestWorkers        40 
MaxConnectionsPerChild   50

This was followed with a quick restart of Apache to apply the changes:

sudo apachectl restart

I headed to the site and logged onto a test course, trying out some searches in the Library Browser and found that things were improved: I could still see in htop that processes were eating up memory, but they would quickly be killed off and the memory returned to the system. I may have to tweak things when students start logging in and hitting the server with a lot of simultaneous, small requests, but for now so far so good.

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Introducing Patch Notes

2018 was a wild year for me. I had a kid, moved into a new, more technical role at work, and while I haven’t quite yet finished grad school, I’m now close enough that I feel the senioritis kicking in! All that is to say I’m looking forward to what I can achieve in 2019 as I finish school and continue my journey into dad-hood, but it’s the still-new job – Technology Solutions Architect at the University of Portland – that’s the subject of this post.

Moving from the world of edtech, which involved supporting, training, and consulting with faculty on technology tools, to now building, deploying, and administering those tools has been a major transition. As I think about what I know, and what I don’t know, I’ve been reflecting on what helped me to be successful in previous roles and what I can bring to my new one. Something that has stuck out is that I’ve made a habit of teaching, tutoring, writing and making video content that engages with my field. This serves multiple purposes:

  1. I firmly believe that teaching something, whether that’s by presenting on a topic or creating a how-to guide is one of the best ways to build and retain a deep understanding.
  2. It helps me to show what I know and documents my growth in my new field.
  3. Hopefully my content can help others who are in or aspire to learn more about the type of work I’m doing. I’m still in Higher Ed, after all!

So, enter this blog. I’m calling the WordPress category for these posts  “Patch Notes” – it’s my way to reflect on and document my professional growth. Possible topics include:

Moodle, WordPress, Linux, databases, cloud computing, open source, education technology, higher ed, Office 365, and more.

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