It has been a busy few months for Kernl. Lots of great work has gone into the WordPress load testing feature work as well as a few structural changes to increase reliability.
Cache moved to Redis – For as long as Kernl has existed our cache backend was powered by Memcached. We have now finished migrating to Redis hosted at Compose.io.
AngularJS Upgrade to 1.7.5 – Fairly straight-forward upgrade to Angular 1.7.5. We wanted to take advantage of performance improvements and few bug fixes.
WordPress Load Testing – Over the past few months we’ve been cooking up something new. Imagine if you could easily test performance changes to you or your client’s WordPress installation? Or be able to tell your client with confidence how many customers at a time their site can support (and what their experience will be like!). What if you could do all this without writing a single line of code or spinning up your own testing infrastructure? We’re ready to start beta testing so send an email to email@example.com if you would like to be a part of it.
Today we launched the next iteration of Kernl Analytics. The agency plan has been long in the making and we hope that you enjoy the new insights that you can extract with it.
The Kernl Analytics agency plan is very similar to the “small” plan with two key differences:
Increased DataRetention – When the agency plan is selected, Kernl will hold on to your analytics data for 90 days (instead of the small plan’s single day). This also means that you can select a day in the past and see your analytics for it.
Compare Dates – With the agency plan you can select two dates and compare their data against each other. This is extremely useful if you would like to see adoption curves for WordPress versions, PHP versions, and installed versions of your plugin/theme. It allows you to make smart business decisions based on real data.
The Kernl Analytics agency plan is now available to all Kernl customers. The fee is $30/month on top of your existing Kernl plan. Reach out to firstname.lastname@example.org if you have any questions!
Below is a post-mortem analysis of Kernl’s August 14 2018 outage. It details what happened, why it happened, and how we can improve things so that this doesn’t happen again in the future.
At 9:29PM EDT alerts were triggered saying that Kernl was down. Initial investigation showed that the marketing site was still up and that some (but not all) update requests were still going through. Upon further investigation, it was found that Kernl’s connection to MongoDB had stopped working.
In most situations the DB connection dropping would have caused only a momentary blip while we failed over to our secondary, but in this case that wasn’t possible.
Further investigation revealed that our Mongo provider (Compose.io) was experiencing an outage in some of their Digital Ocean environments. Unfortunately this outage effected not only our primary Mongo host but also our backup secondary host. Due to the nature of the outage automatic failover for Mongo wasn’t a possibility.
Determined the source of the downtime.
Contacted Compose.io support to resolve the issue.
After not hearing back from support for 30 minutes, work was started on an alternate plan for bringing Kernl back up.
After 45 minutes of no response from Compose.io support the alternate plan was enacted.
The alternate plan was to restore Kernl’s Mongo cluster into a different data center using the daily backup. The only downside was that that backup was 6 hours old, which means there is a possibility that customers will need to re-build or re-upload some plugin and theme versions.
Cache lifetime for all Kernl endpoints was doubled. This was done because the new data center was outside of Digital Ocean NYC3. The increased cache lifetime helps combat the increased latency.
Kernl’s downtime ended at roughly 11:00PM. The Compose.io incident wasn’t resolved until several hours after this so we feel that the decision to restore from a backup was the right one.
Compose.io has been our Mongo provider for years now and we’ve never experienced any significant downtime. That being said, they don’t actually support DigitalOcean anymore and plan to kill their support for it at sometime in the future.
Our next steps are to evaluate how Kernl performs with the database in another data center. If things look good, we will likely move Kernl’s Mongo instances to the new data center permanently where they can be better supported by Compose. It is our suspicion that if we had been in one of their more popular data centers that we would have received help faster.
Once again, apologies for the downtime and we’ll continue to work hard so that it doesn’t happen again!
Happy (almost) August everyone! This month with Kernl was focused on fixing some technical debt and adding a few features surrounding analytics.
Features & Bug Fixes
Analytics Top Level Menu – Kernl Analytics now has a top-level menu item. Prior to this change you had to enter a plugin/theme page before you could access it.
Analytics Product & Date Selector – Coupled with the analytics top-level menu, you can now select which product you want to see analytics for directly in the page. You can also select the date if you have the “agency” plan or above.
Session Store Moved to Memcached – For most of Kernl’s life sessions have been stored in Mongo. Recently we moved to storing sessions in Memcached.
GitLab Integration Bug Fix – The GitLab integration was broken for a few days after GitLab disabled their v3 API. This has been resolved.
The .kernlignore file had a few bugs related to processing it. These have been resolved.
Along with the session storage change we cleaned up a few collections in Mongo.
I hope everyone in the northern hemisphere is enjoying their summer and for those of you in the southern hemisphere, stay warm! It was a nice month for Kernl with lots of good structural changes and a few new features rolled out.
SendOwl Integration – If you use SendOwl to distribute your plugin or theme you can now validate license keys with Kernl. This means that every time a customer checks to see if an update is available Kernl will first validate their SendOwl license.
Analytics Aggregate Data – Kernl Analytics now uses aggregate data to populate charts. This means that charts load instantly versus taking a few seconds as they did before. This was a big change and enables us to do neat things in the future like calculating changes over time.
Analytics Domains – In addition to using aggregate data to populate charts Kernl Analytics now has improved domain list support. Data is properly paginated, populated via aggregates for speed, and searchable.
Version Number Improvements – Kernl now supports version numbers such as 10.2.2-alpha or 9.2.1-beta. Previously the alpha|beta tags at the end were not supported.
Download Graph Bug Fix – A customer reported that the download chart in the plugin/theme detail pages weren’t quite right. This bug has been fixed.
License Management – The license management page was occasionally showing duplicates. This bug has been fixed.
It’s been a great month for Kernl! Lots of new features, some bug fixes, and few updates to the license checking on the plugin and theme update checker files. Lets dive in!
Gumroad License Validation – You can now use Kernl to validate your Gumroad licenses! This can be enabled for plugins or themes by going to the product edit screen, clicking the “License Management” tab, and then selecting “Validate Gumroad License?” at the bottom.
Kernl Referral Program – Kernl has a referral program. For every 3 referrals you send us we’ll give you a free month. Customers signing up with your referral code get their first 3 months free.
Restrict Updates to a Maximum Version – If you use Kernl’s license management you can now restrict update availability to a maximum version. For example if the current version of your product was 1.5.0 and you gave the user a license for < 1.6.0, then they would receive updates all the way through 1.5.X. This is a great way to drive more sales of your product!
Plugin/Theme PHP Update Check Files – The license error display behavior of these files has been greatly improved. The error dismisses when it’s supposed to, only shows up on the updates and plugin|theme page, and the license error message can now be customized. It is highly recommended that you update. The file is also versioned now so knowing when to update in the future will be much easier.
Purchase Code Deprecation – Kernl’s old purchase code frontend interface has been hidden behind a feature flag. The goal is the have the old purchase code functionality completely removed by the end of July.
Copy Versions from Product to Product – To support special development styles, you can move versions of a product to another product. This is inherently dangerous and only toggled on for the person who requested it. If you think this might be useful please reach out to email@example.com.
You can now easily click to a customer’s page from the License Management page.
A bug was fixed where the customer filter would stay set even after you had navigated away from that page.
Numerous copy changes were made on the License Management page and on the marketing site.
Some feature flags were removed from features that have proved to be stable.
The main route for plugin update checks (also the highest traffic route on Kernl) was refactored to use async/awaitinstead of promise chains. This makes it much easier to maintain and improve.
If you use Gumroad to sell your WordPress plugins or themes you can now use Kernl to validate those licenses before new updates are made available.
How does it work?
When you create a plugin/theme in Kernl you can select the “Validate Gumroad License?” checkbox and fill out the “Gumroad Product Permalink” field. With those two fields completed Kernl will validate the license code passed into the Kernl via the update checker against Gumroad’s public license API. If the license code passes validation Kernl will allow the update to proceed.
That’s all there is to it! If you need any help getting things set up reach out to firstname.lastname@example.org.
Kernl WordPress license management now allows you to limit updates up to a specific version.
How it Works
Assuming that you already use Kernl’s license management, go to the License Management area of Kernl. Once there add or edit a license.
Now you can fill in the “Max Update Version” field. This field can simply be described as “the version of your product which requires a customer to buy a new license”. For example:
Customer A bought a license with “Max Update Version” set to 2.0.0. The product was at version 1.7.0 at the time of purchase. Over the next few months you release 1.8.0, 1.9.0, 1.9.1, 2.0.0, 2.0.1. Customer A only receives product update versions 1.8.0, 1.9.0, and 1.9.1.
Why should I use this?
Drive. More. Sales. This new feature allows you to be extremely granular about what updates a specific customer receives. We also made updates to plugin_update_check.php and theme_update_check.php that allow you to customize the invalid/expired license message. We strongly believe that this combination of better license expiration messages and limiting through specific update version can be instrumental in helping you drive more sales.
For most of Kernl’s life our best channel for adding new customers has been word-of-mouth referrals and now you can be rewarded for referring new customers!
How It Works
When you go to your Kernl profile you’ll see a new section called “Referrals”.
It briefly explains how the Kernl referral program works, gives you your referral link, tells you how many referrals you’ve made, and how many free months you’ve earned.
The rewards for the Kernl referral program are as follows:
For the referrer: Every 3 customers you refer to Kernl earn you one free month. No restrictions on plan or usage. There is a max of 24 referrals. If you somehow manage to bump in to this restriction, shoot us an email and we’ll work with you. 🙂
For the new customer: By using your referral code they earn 3 free months of Kernl (instead of the usual 30 day free trial).
That’s it! Kernl’s referral program is intentionally simple. Thanks to everyone who spreads the word about Kernl. The more customers we have the better we become.
Data Export – You can now export (most) of your Kernl data. To export your data, log in to Kernl, go to your profile, and scroll down to the “Export My Data” button.
Node.js Upgraded – Kernl has been updated to use the latest LTS version of Node.js. We are now on 8.11.1.
Kernl Analytics Hardware Upgraded – Kernl analytics sees a lot of traffic on a daily basis. As that number continued to grow we were seeing some resource contention issues during peak periods. We were able to mitigate all resource issues by upgrading our hardware from a single vCPU setup to a three vCPU setup.
https://kernl.us/wordpress-installation-statistics – Check out our new public WordPress installation statistics page! Most of this information is readily available on WordPress.org, but Kernl’s data is interesting because it only includes data points from websites that purchase plugins or themes. The data is also available via our API for public consumption.
Thats it for this month! I hope everyone in the northern hemisphere is enjoying the start of summer.