diff --git a/nixos/modules/virtualisation/amazon-image.nix b/nixos/modules/virtualisation/amazon-image.nix index 44cb6080945..819e93a43e5 100644 --- a/nixos/modules/virtualisation/amazon-image.nix +++ b/nixos/modules/virtualisation/amazon-image.nix @@ -11,6 +11,7 @@ with lib; let cfg = config.ec2; metadataFetcher = import ./ec2-metadata-fetcher.nix { + inherit (pkgs) curl; targetRoot = "$targetRoot/"; wgetExtraOptions = "-q"; }; diff --git a/nixos/modules/virtualisation/ec2-metadata-fetcher.nix b/nixos/modules/virtualisation/ec2-metadata-fetcher.nix index b531787c31a..247bcf513c5 100644 --- a/nixos/modules/virtualisation/ec2-metadata-fetcher.nix +++ b/nixos/modules/virtualisation/ec2-metadata-fetcher.nix @@ -1,23 +1,58 @@ -{ targetRoot, wgetExtraOptions }: +{ curl, targetRoot, wgetExtraOptions }: +# Note: be very cautious about dependencies, each dependency grows +# the closure of the initrd. Ideally we would not even require curl, +# but there is no reasonable way to send an HTTP PUT request without +# it. Note: do not be fooled: the wget referenced in this script +# is busybox's wget, not the fully featured one with --method support. +# +# Make sure that every package you depend on here is already listed as +# a channel blocker for both the full-sized and small channels. +# Otherwise, we risk breaking user deploys in released channels. '' metaDir=${targetRoot}etc/ec2-metadata mkdir -m 0755 -p "$metaDir" + get_imds_token() { + # retry-delay of 1 selected to give the system a second to get going, + # but not add a lot to the bootup time + ${curl}/bin/curl \ + -v \ + --retry 3 \ + --retry-delay 1 \ + --fail \ + -X PUT \ + --connect-timeout 1 \ + -H "X-aws-ec2-metadata-token-ttl-seconds: 600" \ + http://169.254.169.254/latest/api/token + } + + try=1 + while [ $try -le 3 ]; do + echo "(attempt $try/3) getting an EC2 instance metadata service v2 token..." + IMDS_TOKEN=$(get_imds_token) && break + try=$((try + 1)) + sleep 1 + done + + if [ "x$IMDS_TOKEN" == "x" ]; then + echo "failed to fetch an IMDS2v token." + fi + echo "getting EC2 instance metadata..." if ! [ -e "$metaDir/ami-manifest-path" ]; then - wget ${wgetExtraOptions} -O "$metaDir/ami-manifest-path" http://169.254.169.254/1.0/meta-data/ami-manifest-path + wget ${wgetExtraOptions} --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" -O "$metaDir/ami-manifest-path" http://169.254.169.254/1.0/meta-data/ami-manifest-path fi if ! [ -e "$metaDir/user-data" ]; then - wget ${wgetExtraOptions} -O "$metaDir/user-data" http://169.254.169.254/1.0/user-data && chmod 600 "$metaDir/user-data" + wget ${wgetExtraOptions} --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" -O "$metaDir/user-data" http://169.254.169.254/1.0/user-data && chmod 600 "$metaDir/user-data" fi if ! [ -e "$metaDir/hostname" ]; then - wget ${wgetExtraOptions} -O "$metaDir/hostname" http://169.254.169.254/1.0/meta-data/hostname + wget ${wgetExtraOptions} --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" -O "$metaDir/hostname" http://169.254.169.254/1.0/meta-data/hostname fi if ! [ -e "$metaDir/public-keys-0-openssh-key" ]; then - wget ${wgetExtraOptions} -O "$metaDir/public-keys-0-openssh-key" http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key + wget ${wgetExtraOptions} --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" -O "$metaDir/public-keys-0-openssh-key" http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key fi ''