TFS Build Agent - SSL certificate problem: unable to get local issuer certificate

After upgrading to a new TFS server and going full HTTPS, our git based builds started to fail with the following error message:

2018-06-12T21:28:45.8463514Z ##[command]git init "D:\Builds\dev-agent-1\_work\5\s"

2018-06-12T21:28:45.9154418Z Initialized empty Git repository in D:/Builds/dev-agent-1/_work/5/s/.git/

2018-06-12T21:28:45.9219662Z ##[command]git remote add origin https://tfs/DefaultCollection/_git/Sample

2018-06-12T21:28:45.9821910Z ##[command]git config gc.auto 0

2018-06-12T21:28:46.0407163Z ##[command]git config --get-all http.https://tfs/DefaultCollection/_git/Sample.extraheader

2018-06-12T21:28:46.0994413Z ##[command]git config --get-all http.proxy

2018-06-12T21:28:46.1508406Z ##[command]git -c http.extraheader="AUTHORIZATION: bearer ********" fetch --tags --prune --progress --no-recurse-submodules origin

2018-06-12T21:28:46.3636860Z fatal: unable to access 'https://tfs/DefaultCollection/_git/Sample/': SSL certificate problem: unable to get local issuer certificate

2018-06-12T21:28:46.3988694Z ##[error]Git fetch failed with exit code: 128

2018-06-12T21:28:46.4040002Z ##[section]Finishing: Get Sources

The SSL certificate we are using is based on a corporate root certificate. This root certificate is stored in the certificate store on all the servers .Any application written to use the Windows crypto APIs will have access to that root certificate, and will consider your TFS deployment to be trusted.

Unfortunately, Git for Windows (git.exe) uses OpenSSL for its crypto stack, and the Git for Windows distribution includes a set of trusted root certificates in a simple text file. As our root certificate is not in this set, we’ll get the error above.

An easy workaround we used at first was to add the following configuration setting on the global git config available at c:\programdata\git

[http] sslVerify=false

As this globally disables TLS(/SSL) certificate verification, it is not a solution I would recommend. This defeats the purpose of introducing SSL in the first place.

We’ll have to find a better solution, but we’ll leave that for another blog post…

Podman– Command execution failed with exit code 125

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A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...

The art of simplicity

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