Update debian used in gitian build guide to version 8.1 #6419

The 7.8.0 iso went poof, and it is better to use a newer version: e.g. newer versions are provided with signatures by Debian themselves.

I'd prefer a more stable URI but there doesn't appear to be one. So when 8.2 is released, the link will break again, and we have to update the document again.

Note: not tested, still need to go through this guide with 8.1

utACK, had a similar pull open at theuni's trivial branch for 8.0, closed in favour of this one. Will run through the guide again with 8.1.

This could just be me, but I've experienced a few (fixable) issues and differences with Debian 8.1 in combination with 0.10.2:

• the setup was slightly different than before
• SSH login as root is disabled (if required -> PermitRootLogin yes)
• when trying to setup Gitian, as described in Setting up gitian images, I saw the following error:

bin/make-base-vm: 117: bin/make-base-vm: mkfs.ext4: not found

A post on dashtalk.org suggests:

$ git diff
diff --git a/bin/make-base-vm b/bin/make-base-vm
index 7fc7818..e51b1a2 100755
--- a/bin/make-base-vm
+++ b/bin/make-base-vm
@@ -114,7 +114,7 @@ if [ $LXC = "1" ]; then
   # Need universe for lxc in lucid
   env -i LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 sudo debootstrap --arch=$ARCH --include=$addpkg --exclude=$removepkg --components=main,universe $SUITE $OUT-bootstrap $MIRROR
   dd if=/dev/zero of=$OUT-lxc bs=1M count=1 seek=10240
-  mkfs.ext4 -F $OUT-lxc
+  sudo mkfs.ext4 -F $OUT-lxc
   t=`mktemp -d gitian.XXXXXXXX`
   sudo mount $OUT-lxc $t
   sudo cp -a $OUT-bootstrap/* $t

Or alternatively:

$ export PATH=$PATH:/sbin

• when trying to build without dependencies, then it fails, because wget isn't available for Gitian:

# ~/gitian-builder/var/build.log:
+ for i in '$HOSTS'
+ make -j2 -C /home/ubuntu/build/bitcoin/depends HOST=x86_64-w64-mingw32
make: Entering directory `/home/ubuntu/build/bitcoin/depends'
Fetching native_ccache...
/bin/sh: 1: wget: not found

Manually downloading the dependencies helps:

$ make -C ../bitcoin/depends download SOURCES_PATH=`pwd`/cache/common

@dexX7 Thanks for trying it out!

7.8 didnt go poof it was just archived. See #6439

ACK

ACK. But required rebase.

I don't think this ready for ACK. From @dexX7 's attempt it's apparent that there need to be some non-trivial changes before 8.x can be used. That's why I merged #6439 first.

bin/make-base-vm: 117: bin/make-base-vm: mkfs.ext4: not found

Has now been fixed in gitian in https://github.com/devrandom/gitian-builder/commit/ec56a82d4b14872fe27fe10a93a346162318f8f5

I'd suggest we add 'make' to the list of packages installed in Debian on setup so that the depends downloader can be run.

We'll need to modify the guide so that users change PermitRootLogin before they try and SSH in.

Open /etc/ssh/sshd_config and change the following line:
FROM:
PermitRootLogin without-password
TO:
PermitRootLogin yes

I haven't yet checked if this holds true for Debian 8.1. Either way the comment will need to be removed/updated.

# the version of lxc-start in Debian 7.4 needs to run as root, so make sure
# that the build script can exectute it without providing a password
echo "%sudo ALL=NOPASSWD: /usr/bin/lxc-start" > /etc/sudoers.d/gitian-lxc

This screenshot can probably be updated to as it appears in the 8.1 install.

Great summary @fanquake. Even though it's probably unlike that Gitian changes fundamentally, I think it wouldn't hurt to mention the commit/version of Gitian, which was used to create the guide, so this aspect of the environment is exactly reproducible.

I'm currently using https://github.com/devrandom/gitian-builder/commit/e3e67df408f451db94a445d90a977d37dbc58b77 (newest commit) in combination with Debian 7.8 and Bitcoin Core 0.10.2 (as underlying code base):

• it was also necessary to download the dependencies manually, because wget appearingly isn't available; haven't tested to add make, as hinted in #6419 (comment)
• when building, there is a bunch of extra output related to lxc-start and dpkg, which doesn't seem to do any harm, but it's a bit distracting

Closing in favor of #6626