1
Jun, 2020
Using Unison Across Linux, macOS, and Windows
CloudI recently wrapped up an instance where I needed to use the Unison file synchronization application across Linux, macOS, and Windows. While Unison is available for all three platforms and does work across (and among) systems running all three operating systems, I did encounter a few interoperability issues while making it work. Here’s some information on these interoperability issues, and how I worked around them. (Hopefully this information will help someone else.)
The use case here is to keep a subset of directories in sync between a MacBook Air running macOS “Catalina” 10.15.5 and a Surface Pro 6 running Windows 10. A system running Ubuntu 18.04.4 acted as the “server”; each “client” system (the MacBook Air and the Surface Pro) would synchronize with the Ubuntu system. I’ve used a nearly-identical setup for several years to keep my systems synchronized.
One thing to know about Unison before I continue is that you need compatible versions of Unison on both systems in order for it to work. As I understand it, compatibility is not just based on version numbers, but also on the Ocaml version with which it was compiled.
With that in mind, I already had a working setup using Unison 2.48 so I started there. Unison 2.48.4 was installed and running on the Ubuntu system, and I installed Unison 2.48.15 on the new MacBook Air. I’d used Unison 2.48.15 on macOS for quite a while, so I didn’t test the installation right away, instead moving on to the Surface Pro. From this page hosting Windows binaries for Unison, I downloaded a Unison 2.48.4 binary for Windows. Should be all set, right?
Unfortunately, I ran into a couple problems:
- The Windows binary has an issue where it won’t recognize the preinstalled OpenSSH binary on Windows 10. So, I had to copy
ssh.exeto the same directory as the Unison binary. - The Windows binary didn’t like paths with spaces in the name; no style of quoting seemed to help. The only workaround I could find was to use
dir /Xto get the auto-generated short name, and use that in the Unison profile.
Once past those two issues I managed to successfully get Unison to synchronize files between the Surface Pro and the Ubuntu system. Moving on to the MacBook Air—which I honestly suspected would be the easy step—I found Unison 2.48 crashed on macOS 10.15. Nothing would make it run without crashing.
Some continued research led me to find Windows and macOS builds of a newer version of Unison, version 2.51. The changelog referenced APFS support, which is what was being used on the MacBook Air. That should do it, right?
- Unison 2.51 wouldn’t interoperate with the existing Unison 2.48 binary on the Ubuntu system. (Recall that I mentioned earlier that compatible versions of Unison were needed on both systems.)
- There were no packaged versions of Unison 2.51 for Ubuntu.
Fortunately, cloning the GitHub repository and building from source was pretty straightforward. I changed the filename of the new version (I used unison-2.51.2) and changed the “servercmd” setting in the Unison preferences on both the Surface Pro and the MacBook Air. Success! I was able to run Unison to synchronize files between the Surface Pro, the Ubuntu system, and the MacBook air running macOS 10.15.
Lessons learned?
- Unison’s support on Windows for paths with spaces is tricky. Use
dir /Xto get the auto-generated short name and use that instead. - On Windows 10, you’ll need to copy
ssh.exefromC:\Windows\System32\OpenSSHto the directory where the Unison executable resides. Otherwise, Unison will be unable to initiate the SSH connection to the remote system. - If you’re running macOS 10.15, be sure to use Unison 2.51. (This may apply to all systems running APFS, but I haven’t verified that yet.)
- Pre-compiled binaries for Unison 2.51 are available for both Windows and macOS, so that’s probably the best version to use. For Linux, it’s very likely you’ll need to build from source in order to get a version 2.51 binary.
I hope this information is helpful to others who may need to get Unison working across multiple systems. If you have corrections, suggestions for improvement, or feedback on how I can improve this post, please contact me on Twitter. Thanks!
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1
Jun, 2020
The Future of Payments
Cloud Articles, Fintech, Mobile, payment
29
May, 2020
Technology Short Take 127
CloudWelcome to Technology Short Take #127! Let’s see what I’ve managed to collect for you this time around…
Networking
- Banzai Cloud’s Toader Sebastian explains how to write WASM (WebAssembly) filters for Envoy and deploy those filters with Istio. Be forewarned—this is a bit of an advanced topic.
- Ivan Pepelnjak provides a 101-level overview of AWS networking.
- This recent post by Eric Sloof shows how to do BGP neighbor adjacency between GNS3 and NSX-T 3.0.
- Andrew Sy Kim tackles explaining a (somewhat) obscure part of Kubernetes networking: the
externalTrafficPolicysetting. Read his write-up here.
Servers/Hardware
Nothing this time around, but I’ll stay alert for items to include next time!
Security
- Ubuntu 20.04 has backported support for WireGuard in its 5.4-based kernel, but for earlier versions some additional work is needed. Here’s a write-up on setting up WireGuard on Ubuntu 18.04.
- Bruce Schneier weighs in on the security and privacy implications of Zoom. (And while we’re on the topic of Zoom, I’d love to hear your thoughts on their acquisition of Keybase.)
- Some security vulnerabilities with Thunderbolt were recently discovered and disclosed. See this website for more details.
- Looking for some security tools? Look no further.
Cloud Computing/Cloud Management
- Reader Witold Duranek contacted after Technology Short Take 126 to thank me for the useful information the series provides, and to mention that she (he?) has been writing some stuff during the Kubernetes learning process. Check it out—you may find something useful here.
- Jason Price shares a fully fleshed-out example of Kubernetes Pod Security Policies.
- Ravi Jagannathan provides an overview of using Velero to do backups and restores on Kubernetes.
- Michael Kashin takes a stroll through Cluster API using the Cluster API Provider for Docker (CAPD).
- Christian Posta of Solo.io tackles the question of whether an API gateway is needed if a service mesh is present. I haven’t dug deep enough into this space (yet) to have an informed opinion, but from my uninformed perspective it seems that these two technologies are more complementary than competitive.
- Ben Kehoe laments some of CloudFormation’s shortcomings in acting like a proper infrastructure graph management service.
- Kyle Galbraith takes readers through the use of AWS Organizations to simplify billing for multiple accounts.
- Adin Ermie provides a review of Managing Kubernetes, a book by Brendan Burns and my colleague Craig Tracey.
- Here are some resources for learning Kubernetes.
Operating Systems/Applications
- Nicola Apicella has a nice, in-depth write-up discussing Docker images, overlay file systems, and the OCI specification.
- Kirill Shirinkin has a four-part “Dockerless” series going (part 1, part 2, part 3, and part 4) that discusses replacing Docker with…well, something else.
- Mat Jovanovic shares the story of how he moved from Blogger to Hugo on AWS.
- This article provides some information on how Bash startup files are used by the shell.
- Brian Vanderwal writes about Git’s worktree feature, which looks to be really handy.
- I can’t immediately think of a use case for this configuration, but it’s handy to know it’s possible if necessary.
Storage
I don’t have anything to share this time, but maybe check here for something that strikes your interest?
Virtualization
- For those new to Linux virtualization—or even if you’ve been around Linux virtualization for a while—this article explaining how Intel VT-x, QEMU, and KVM work together is full of good information.
- Tomas provides resources for running Fedora Silverblue on Libvirt/KVM.
Career/Soft Skills
- Former manager and colleague Paul Lundin penned this piece about working in a startup versus working in an enterprise back in June 2018. There are some very salient points here for folks trying to decide their career path.
- Matthias Ender has an amusing collection of stories around the origins of various computer terms.
- Here are some templates for Wardley mapping. If you don’t know what Wardley mapping is, see here.
That’s all for now! I hope I have included something that is useful to you. If you have feedback or suggestions for improvement, I’d love to hear from you (reaching me on Twitter is probably easiest). Thanks for reading!
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