Lev Lazinskiy

Alpine Linux, wget, and ca-certificates

I’ve been working with Alpine Linux this week. This tiny Linux distribution is an excellent choice for a base docker image or, in my case, for a low power VPS. I love how easy and fast it is to install and configure this distribution.

One stumbling block that I ran into was downloading random things from the internet with wget.

Unable to locally verify the issuer's authority.
To connect to dl.eff.org insecurely, use `--no-check-certificate'

I saw this timely tweet by Joe Gross the other day and decided that rather than ignoring the error messages that wget was throwing I would go and figure out what was wrong.

It turns out that when you make an 83MB distribution you need to cut some of the fat. The ca-certificates package that is common in every Linux Distribution under the sun is missing from the default installation of Alpine.

In order to resolve the angry warnings from wget, you can install the ca-certificates package with the following command:

apk -U add ca-certificates

This will make wget happy, and your server secure. In case you are wondering, skipping this step and running wget with –no-check-certificate totally works. However, it is also inviting a man in the middle attack. Don’t ever do this.