I run debootstrap like this:

sudo debootstrap --verbose --arch=amd64 zesty chroot

I have already installed apt-cacher-ng.

How do I make them work together so that when I run debootstrap multiple times I use the cache instead of repeatedly downloading the same packages?

I have tried using the MIRROR option and setting the http_proxy variable but it errors when I run offline:

$ sudo http_proxy="http://localhost:3142" debootstrap --verbose --arch=amd64 zesty chroot http://localhost:3142/uburep
I: Retrieving InRelease 
I: Failed to retrieve InRelease
I: Retrieving Release 
E: Failed getting release file http://localhost:3142/uburep/dists/zesty/Release

I used http://localhost:3142/uburep because that is what I found in the cache:

$ find /var/cache/apt-cacher-ng -name Release

I tried adding Defaults env_keep += "http_proxy https_proxy ftp_proxy" to /etc/sudoers (via sudo visudo) but it didn't help either.

If I remove the MIRROR option and run debootstrap offline it then doesn't seem to use apt-cacher-ng at all (note how it is not looking for localhost any more).

E: Failed getting release file http://archive.ubuntu.com/ubuntu/dists/zesty/Release
  • What Ubuntu version is this? Sep 23, 2017 at 22:15
  • zesty. I am creating a zesty iso distribution from within zesty.
    – opticyclic
    Sep 23, 2017 at 22:30
  • You shouldn't use the apt-cacher-ng URL as a mirror. It should be used a proxy only.
    – muru
    Oct 12, 2017 at 5:17
  • I updated the question to demonstrate that removing the MIRROR option doesn't help.
    – opticyclic
    Oct 12, 2017 at 6:29
  • Does apt-cacher's logs indicate any attempt to access it when used only as a proxy?
    – muru
    Oct 12, 2017 at 6:47

1 Answer 1


There is a trick to get this to work without explicit proxy settings. You can in fact use your configured apt-cacher-ng as a mirror URL like so:


So as you can see after specifying the base URL to your apt-cacher-ng instance you can then give a server and a path as per this Wiki article. I've used this method in my own bootstrap scripts and it works like a charm.

Note: you may want to verify that your apt-cacher-ng instance is running by checking with lsof -i :3142 (requires the lsof package).

  • I mention in the question that I am using the mirror option and it doesn't work when I am offline. What are you doing differently here?
    – opticyclic
    Dec 1, 2017 at 21:45
  • 0xC… is using the same option as you.
    – Ken Sharp
    Jun 22, 2018 at 10:58

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