apt-get update fails with 404 in a previously working build : <p>I am running a Travis build and it fails when building the mysql:5.7.27 docker image. The Dockerfile runs <code>apt-get update</code> and then I get an error <code>W: Failed to fetch http://deb.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages  404  Not Found</code>.</p>

<p>Using curl I can see it is redirecting, but the redirect-to URL results in a 404. Has anyone seen this sort of behaviour and have a remedy? Is it basically unfixable until debian makes changes?</p>

<pre><code>➜  ms git:(develop) curl --head http://deb.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages
HTTP/1.1 302 Found
Date: Tue, 26 Mar 2019 16:03:04 GMT
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Location: http://cdn-fastly.deb.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages
Content-Type: text/html; charset=iso-8859-1

➜  ms git:(develop) curl --head http://cdn-fastly.deb.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages
HTTP/1.1 404 Not Found
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Content-Type: text/html; charset=iso-8859-1
Via: 1.1 varnish
Content-Length: 316
Accept-Ranges: bytes
Date: Tue, 26 Mar 2019 16:03:17 GMT
Via: 1.1 varnish
Age: 45
Connection: keep-alive
X-Served-By: cache-ams21028-AMS, cache-cdg20741-CDG
X-Cache: HIT, HIT
X-Cache-Hits: 6, 2
X-Timer: S1553616198.734091,VS0,VE0
</code></pre>
