534a01c2b0
curl does not retry if it is unable to connect to the metadata server. For some reason, when creating a new AMI with a recent nixpkgs, the metadata server would not be available when fetch-ec2-data ran. Switching to wget that can retry even on TCP connection errors solved this problem. I also made the fetch-ec2-data depend on ip-up.target, to get it to start a bit later.
101 lines
3.6 KiB
Nix
101 lines
3.6 KiB
Nix
# This module defines a systemd service that obtains the SSH key and
|
|
# host name of virtual machines running on Amazon EC2, Eucalyptus and
|
|
# OpenStack Compute (Nova).
|
|
|
|
{ config, lib, pkgs, ... }:
|
|
|
|
with lib;
|
|
|
|
{
|
|
options = {
|
|
ec2.metadata = mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
description = ''
|
|
Whether to allow access to EC2 metadata.
|
|
'';
|
|
};
|
|
};
|
|
|
|
config = {
|
|
|
|
systemd.services."fetch-ec2-data" =
|
|
{ description = "Fetch EC2 Data";
|
|
|
|
wantedBy = [ "multi-user.target" "sshd.service" ];
|
|
before = [ "sshd.service" ];
|
|
wants = [ "ip-up.target" ];
|
|
after = [ "ip-up.target" ];
|
|
|
|
path = [ pkgs.wget pkgs.iproute ];
|
|
|
|
script =
|
|
''
|
|
ip route del blackhole 169.254.169.254/32 || true
|
|
|
|
wget="wget -q --retry-connrefused -O -"
|
|
|
|
echo "setting host name..."
|
|
${optionalString (config.networking.hostName == "") ''
|
|
${pkgs.nettools}/bin/hostname $($wget http://169.254.169.254/1.0/meta-data/hostname)
|
|
''}
|
|
|
|
# Don't download the SSH key if it has already been injected
|
|
# into the image (a Nova feature).
|
|
if ! [ -e /root/.ssh/authorized_keys ]; then
|
|
echo "obtaining SSH key..."
|
|
mkdir -p /root/.ssh
|
|
$wget http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key > /root/key.pub
|
|
if [ $? -eq 0 -a -e /root/key.pub ]; then
|
|
if ! grep -q -f /root/key.pub /root/.ssh/authorized_keys; then
|
|
cat /root/key.pub >> /root/.ssh/authorized_keys
|
|
echo "new key added to authorized_keys"
|
|
fi
|
|
chmod 600 /root/.ssh/authorized_keys
|
|
rm -f /root/key.pub
|
|
fi
|
|
fi
|
|
|
|
# Extract the intended SSH host key for this machine from
|
|
# the supplied user data, if available. Otherwise sshd will
|
|
# generate one normally.
|
|
$wget http://169.254.169.254/2011-01-01/user-data > /root/user-data || true
|
|
key="$(sed 's/|/\n/g; s/SSH_HOST_DSA_KEY://; t; d' /root/user-data)"
|
|
key_pub="$(sed 's/SSH_HOST_DSA_KEY_PUB://; t; d' /root/user-data)"
|
|
if [ -n "$key" -a -n "$key_pub" -a ! -e /etc/ssh/ssh_host_dsa_key ]; then
|
|
mkdir -m 0755 -p /etc/ssh
|
|
(umask 077; echo "$key" > /etc/ssh/ssh_host_dsa_key)
|
|
echo "$key_pub" > /etc/ssh/ssh_host_dsa_key.pub
|
|
fi
|
|
|
|
${optionalString (! config.ec2.metadata) ''
|
|
# Since the user data is sensitive, prevent it from being
|
|
# accessed from now on.
|
|
ip route add blackhole 169.254.169.254/32
|
|
''}
|
|
'';
|
|
|
|
serviceConfig.Type = "oneshot";
|
|
serviceConfig.RemainAfterExit = true;
|
|
};
|
|
|
|
systemd.services."print-host-key" =
|
|
{ description = "Print SSH Host Key";
|
|
wantedBy = [ "multi-user.target" ];
|
|
after = [ "sshd.service" ];
|
|
script =
|
|
''
|
|
# Print the host public key on the console so that the user
|
|
# can obtain it securely by parsing the output of
|
|
# ec2-get-console-output.
|
|
echo "-----BEGIN SSH HOST KEY FINGERPRINTS-----" > /dev/console
|
|
${pkgs.openssh}/bin/ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub > /dev/console
|
|
echo "-----END SSH HOST KEY FINGERPRINTS-----" > /dev/console
|
|
'';
|
|
serviceConfig.Type = "oneshot";
|
|
serviceConfig.RemainAfterExit = true;
|
|
};
|
|
|
|
};
|
|
}
|