Both binary & source installation failing for ros-gz with ROS2-Iron & Ubuntu Jammy

Question

I'm trying to install ros-gz on my Ubuntu 22.04.3 laptop with ROS2-Iron & Gazebo-fortress already installed (both using binaries).

First I ran sudo apt-get update to which I get:

Hit:1 http://security.ubuntu.com/ubuntu jammy-security InRelease
Hit:2 http://packages.microsoft.com/repos/code stable InRelease                                                                                                      
Hit:3 https://dl.google.com/linux/chrome/deb stable InRelease                                                                                                        
Hit:4 http://packages.ros.org/ros2/ubuntu jammy InRelease                                                                                                            
Hit:5 http://packages.osrfoundation.org/gazebo/ubuntu-stable jammy InRelease                                                                                         
Hit:6 https://packagecloud.io/sensu/stable/ubuntu jammy InRelease                                                          
Hit:7 http://us.archive.ubuntu.com/ubuntu jammy InRelease
Hit:8 http://us.archive.ubuntu.com/ubuntu jammy-updates InRelease
Hit:9 http://us.archive.ubuntu.com/ubuntu jammy-backports InRelease
Reading package lists... Done

Then, as suggested in the 'default ros/gazebo pairing' section of this guide, I ran sudo apt-get install ros-iron-ros-gz & I'm getting the below 404 Not found errors:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-image-transport-plugins ros-iron-ros-gz-bridge ros-iron-ros-gz-image
  ros-iron-ros-gz-interfaces ros-iron-ros-gz-sim ros-iron-ros-gz-sim-demos ros-iron-theora-image-transport
The following NEW packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-image-transport-plugins ros-iron-ros-gz ros-iron-ros-gz-bridge
  ros-iron-ros-gz-image ros-iron-ros-gz-interfaces ros-iron-ros-gz-sim ros-iron-ros-gz-sim-demos ros-iron-theora-image-transport
0 upgraded, 10 newly installed, 0 to remove and 5 not upgraded.
Need to get 2,354 kB/2,670 kB of archives.
After this operation, 24.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Err:1 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-depth-image-transport amd64 3.1.0-1jammy.20231117.112549
  404  Not Found [IP: 140.211.166.134 80]
Err:2 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-image-transport amd64 3.1.0-1jammy.20231117.112554
  404  Not Found [IP: 140.211.166.134 80]
Err:3 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-theora-image-transport amd64 3.1.0-1jammy.20231117.110033
  404  Not Found [IP: 140.211.166.134 80]
Err:4 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-image-transport-plugins amd64 3.1.0-1jammy.20231117.114631
  404  Not Found [IP: 140.211.166.134 80]
Err:5 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-bridge amd64 0.247.0-1jammy.20231117.114732
  404  Not Found [IP: 140.211.166.134 80]
Err:6 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-image amd64 0.247.0-1jammy.20231117.120950
  404  Not Found [IP: 140.211.166.134 80]
Err:7 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-sim amd64 0.247.0-1jammy.20231117.103229
  404  Not Found [IP: 140.211.166.134 80]
Err:8 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-sim-demos amd64 0.247.0-1jammy.20231117.121601
  404  Not Found [IP: 140.211.166.134 80]
Err:9 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz amd64 0.247.0-1jammy.20231117.121640
  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-depth-image-transport/ros-iron-compressed-depth-image-transport_3.1.0-1jammy.20231117.112549_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-image-transport/ros-iron-compressed-image-transport_3.1.0-1jammy.20231117.112554_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-theora-image-transport/ros-iron-theora-image-transport_3.1.0-1jammy.20231117.110033_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231117.114631_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-bridge/ros-iron-ros-gz-bridge_0.247.0-1jammy.20231117.114732_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-image/ros-iron-ros-gz-image_0.247.0-1jammy.20231117.120950_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-sim/ros-iron-ros-gz-sim_0.247.0-1jammy.20231117.103229_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-sim-demos/ros-iron-ros-gz-sim-demos_0.247.0-1jammy.20231117.121601_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz/ros-iron-ros-gz_0.247.0-1jammy.20231117.121640_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

So, I tried sudo apt-get install ros-iron-ros-gz --fix-missing as suggested in the last line of the above output. To which I get:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-image-transport-plugins ros-iron-ros-gz-bridge ros-iron-ros-gz-image
  ros-iron-ros-gz-interfaces ros-iron-ros-gz-sim ros-iron-ros-gz-sim-demos ros-iron-theora-image-transport
The following NEW packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-image-transport-plugins ros-iron-ros-gz ros-iron-ros-gz-bridge
  ros-iron-ros-gz-image ros-iron-ros-gz-interfaces ros-iron-ros-gz-sim ros-iron-ros-gz-sim-demos ros-iron-theora-image-transport
0 upgraded, 10 newly installed, 0 to remove and 5 not upgraded.
Need to get 2,354 kB/2,670 kB of archives.
After this operation, 24.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Err:1 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-depth-image-transport amd64 3.1.0-1jammy.20231117.112549
  404  Not Found [IP: 140.211.166.134 80]
Err:2 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-image-transport amd64 3.1.0-1jammy.20231117.112554
  404  Not Found [IP: 140.211.166.134 80]
Err:3 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-theora-image-transport amd64 3.1.0-1jammy.20231117.110033
  404  Not Found [IP: 140.211.166.134 80]
Err:4 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-image-transport-plugins amd64 3.1.0-1jammy.20231117.114631
  404  Not Found [IP: 140.211.166.134 80]
Err:5 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-bridge amd64 0.247.0-1jammy.20231117.114732
  404  Not Found [IP: 140.211.166.134 80]
Err:6 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-image amd64 0.247.0-1jammy.20231117.120950
  404  Not Found [IP: 140.211.166.134 80]
Err:7 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-sim amd64 0.247.0-1jammy.20231117.103229
  404  Not Found [IP: 140.211.166.134 80]
Err:8 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz-sim-demos amd64 0.247.0-1jammy.20231117.121601
  404  Not Found [IP: 140.211.166.134 80]
Err:9 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-ros-gz amd64 0.247.0-1jammy.20231117.121640
  404  Not Found [IP: 140.211.166.134 80]
Selecting previously unselected package ros-iron-ros-gz-interfaces.
(Reading database ... 351139 files and directories currently installed.)
Preparing to unpack .../ros-iron-ros-gz-interfaces_0.247.0-1jammy.20231117.085929_amd64.deb ...
Unpacking ros-iron-ros-gz-interfaces (0.247.0-1jammy.20231117.085929) ...
Setting up ros-iron-ros-gz-interfaces (0.247.0-1jammy.20231117.085929) ...
Processing triggers for libc-bin (2.35-0ubuntu3.5) ...
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-depth-image-transport/ros-iron-compressed-depth-image-transport_3.1.0-1jammy.20231117.112549_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-image-transport/ros-iron-compressed-image-transport_3.1.0-1jammy.20231117.112554_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-theora-image-transport/ros-iron-theora-image-transport_3.1.0-1jammy.20231117.110033_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231117.114631_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-bridge/ros-iron-ros-gz-bridge_0.247.0-1jammy.20231117.114732_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-image/ros-iron-ros-gz-image_0.247.0-1jammy.20231117.120950_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-sim/ros-iron-ros-gz-sim_0.247.0-1jammy.20231117.103229_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz-sim-demos/ros-iron-ros-gz-sim-demos_0.247.0-1jammy.20231117.121601_amd64.deb  404  Not Found [IP: 140.211.166.134 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-ros-gz/ros-iron-ros-gz_0.247.0-1jammy.20231117.121640_amd64.deb  404  Not Found [IP: 140.211.166.134 80]

So I thought of trying to install ros-gz from source following the instructions here. I ran:

export GZ_VERSION=fortress
mkdir -p ~/ws/src
cd ~/ws/src
git clone https://github.com/gazebosim/ros_gz.git -b iron
cd ~/ws
rosdep install -r --from-paths src -i -y --rosdistro iron

I'm getting similar 404 errors:

executing command [sudo -H apt-get install -y ros-iron-image-transport-plugins]
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following package was automatically installed and is no longer required:
  ros-iron-ros-gz-interfaces
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-theora-image-transport
The following NEW packages will be installed:
  ros-iron-compressed-depth-image-transport ros-iron-compressed-image-transport ros-iron-image-transport-plugins ros-iron-theora-image-transport
0 upgraded, 4 newly installed, 0 to remove and 5 not upgraded.
Need to get 660 kB of archives.
After this operation, 3,529 kB of additional disk space will be used.
Err:1 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-depth-image-transport amd64 3.1.0-1jammy.20231117.112549
  404  Not Found [IP: 64.50.233.100 80]
Err:2 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-compressed-image-transport amd64 3.1.0-1jammy.20231117.112554
  404  Not Found [IP: 64.50.233.100 80]
Err:3 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-theora-image-transport amd64 3.1.0-1jammy.20231117.110033
  404  Not Found [IP: 64.50.233.100 80]
Err:4 http://packages.ros.org/ros2/ubuntu jammy/main amd64 ros-iron-image-transport-plugins amd64 3.1.0-1jammy.20231117.114631
  404  Not Found [IP: 64.50.233.100 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-depth-image-transport/ros-iron-compressed-depth-image-transport_3.1.0-1jammy.20231117.112549_amd64.deb  404  Not Found [IP: 64.50.233.100 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-compressed-image-transport/ros-iron-compressed-image-transport_3.1.0-1jammy.20231117.112554_amd64.deb  404  Not Found [IP: 64.50.233.100 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-theora-image-transport/ros-iron-theora-image-transport_3.1.0-1jammy.20231117.110033_amd64.deb  404  Not Found [IP: 64.50.233.100 80]
E: Failed to fetch http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231117.114631_amd64.deb  404  Not Found [IP: 64.50.233.100 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
ERROR: the following rosdeps failed to install
  apt: command [sudo -H apt-get install -y ros-iron-image-transport-plugins] failed
  apt: Failed to detect successful installation of [ros-iron-image-transport-plugins]

I ran autoclean & autoremove and re-ran the above binary & source installation commands. The outputs are still the same.

Troubleshooting: Output of head -n 20 /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_InRelease is:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Origin: ROS
Label: ROS jammy
Suite: jammy
Codename: jammy
Date: Fri, 29 Dec 2023 06:23:19 UTC
Architectures: i386 amd64 arm64 armhf
Components: main
Description: ROS jammy Debian Repository
MD5Sum:
 bae85853deff5b3319df842a8f597a4c 139069 main/binary-i386/Packages
 42f2cd693ccc79e03f890c1e60518c2e 39083 main/binary-i386/Packages.gz
 ba1f11e611741566ab55f819d4a3c2fd 120 main/binary-i386/Release
 ec65091ea65caeaa2059ee0f8e5a00e1 5431287 main/binary-amd64/Packages
 a3ba72d0b41c1517422ff2b982455db1 1422935 main/binary-amd64/Packages.gz
 6e8bf3a6440d38bb57959b4c19d096c4 121 main/binary-amd64/Release
 b552b11e559995233c7431c6007ab5fe 5281964 main/binary-arm64/Packages
 7f23b7d4afe02ad57bed496bc7be38a0 1386999 main/binary-arm64/Packages.gz

Then running sudo apt-get update produces:

Hit:1 http://us.archive.ubuntu.com/ubuntu jammy InRelease
Hit:2 http://packages.microsoft.com/repos/code stable InRelease                                                                                                      
Hit:3 http://packages.ros.org/ros2/ubuntu jammy InRelease                                                                                                            
Hit:4 http://us.archive.ubuntu.com/ubuntu jammy-updates InRelease                                                                                                    
Hit:5 http://security.ubuntu.com/ubuntu jammy-security InRelease                                                                                                     
Hit:6 http://us.archive.ubuntu.com/ubuntu jammy-backports InRelease                                                                                    
Hit:7 https://dl.google.com/linux/chrome/deb stable InRelease                                                                                          
Hit:8 http://packages.osrfoundation.org/gazebo/ubuntu-stable jammy InRelease                                                     
Hit:9 https://packagecloud.io/sensu/stable/ubuntu jammy InRelease     
Reading package lists... Done

Followed by quickly running head -n 20 /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_InRelease again produces the same exact output (I stored the outputs in text files & did a vimdiff to check) as it did before the apt-get update.

Further apt-cache policy ros-iron-image-transport-plugins produces:

ros-iron-image-transport-plugins:
  Installed: (none)
  Candidate: 3.1.0-1jammy.20231117.114631
  Version table:
     3.1.0-1jammy.20231117.114631 500
        500 http://packages.ros.org/ros2/ubuntu jammy/main amd64 Packages

Please let me know if you want me to run any more commands and paste the outputs. Any help is greatly appreciated. Thanks!

Answer 1

The most common reason for apt get to give a 404 at that stage is that the local cache is out of date with newer packages on the server.

You don't show it in you question above, but your should always run sudo apt-get update recently before you try to apt-get install anything.

Edit: Showing outputs on a clean system

To get a plain system I used: rocker ros:iron you can use rocker or docker run -ti --rm ros:iron

$ rocker ros:iron
Extension volume doesn't support default arguments. Please extend it.
Active extensions []
Writing dockerfile to /tmp/tmpsdba_8nt/Dockerfile
vvvvvv

FROM ros:iron
USER root

^^^^^^
Building docker file with arguments:  {'path': '/tmp/tmpsdba_8nt', 'rm': True, 'nocache': False, 'pull': False}
building > Step 1/2 : FROM ros:iron
building >  ---> 02a3dc6a1cff
building > Step 2/2 : USER root
building >  ---> Using cache
building >  ---> 0e2b2c19908f
building > Successfully built 0e2b2c19908f
Executing command: 
docker run --rm -it 0e2b2c19908f 
root@99488ea50755:/# apt-get update
Get:1 http://packages.ros.org/ros2/ubuntu jammy InRelease [4682 B]
Get:2 http://security.ubuntu.com/ubuntu jammy-security InRelease [110 kB]      
Get:3 http://packages.ros.org/ros2/ubuntu jammy/main amd64 Packages [1423 kB]  
Get:4 http://archive.ubuntu.com/ubuntu jammy InRelease [270 kB]                
Get:5 http://security.ubuntu.com/ubuntu jammy-security/universe amd64 Packages [1047 kB]
Get:6 http://archive.ubuntu.com/ubuntu jammy-updates InRelease [119 kB]        
Get:7 http://security.ubuntu.com/ubuntu jammy-security/restricted amd64 Packages [1582 kB]
Get:8 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages [1332 kB]
Get:9 http://archive.ubuntu.com/ubuntu jammy-backports InRelease [109 kB]      
Get:10 http://security.ubuntu.com/ubuntu jammy-security/multiverse amd64 Packages [44.0 kB]
Get:11 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages [1792 kB]    
Get:12 http://archive.ubuntu.com/ubuntu jammy/restricted amd64 Packages [164 kB]
Get:13 http://archive.ubuntu.com/ubuntu jammy/universe amd64 Packages [17.5 MB]            
Get:14 http://archive.ubuntu.com/ubuntu jammy/multiverse amd64 Packages [266 kB]            
Get:15 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages [1307 kB]    
Get:16 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages [1606 kB]         
Get:17 http://archive.ubuntu.com/ubuntu jammy-updates/restricted amd64 Packages [1611 kB]   
Get:18 http://archive.ubuntu.com/ubuntu jammy-updates/multiverse amd64 Packages [49.8 kB]                                                  
Get:19 http://archive.ubuntu.com/ubuntu jammy-backports/universe amd64 Packages [28.1 kB]                                                  
Get:20 http://archive.ubuntu.com/ubuntu jammy-backports/main amd64 Packages [50.4 kB]                                                      
Fetched 30.4 MB in 7s (4211 kB/s)                                                                                                          
Reading package lists... Done
root@99488ea50755:/# apt-cache policy ros-iron-image-transport-plugins
ros-iron-image-transport-plugins:
  Installed: (none)
  Candidate: 3.1.0-1jammy.20231206.072142
  Version table:
     3.1.0-1jammy.20231206.072142 500
        500 http://packages.ros.org/ros2/ubuntu jammy/main amd64 Packages
root@99488ea50755:/# cat /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_InRelease | head -n 20
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Origin: ROS
Label: ROS jammy
Suite: jammy
Codename: jammy
Date: Fri, 29 Dec 2023 06:23:19 UTC
Architectures: i386 amd64 arm64 armhf
Components: main
Description: ROS jammy Debian Repository
MD5Sum:
 bae85853deff5b3319df842a8f597a4c 139069 main/binary-i386/Packages
 42f2cd693ccc79e03f890c1e60518c2e 39083 main/binary-i386/Packages.gz
 ba1f11e611741566ab55f819d4a3c2fd 120 main/binary-i386/Release
 ec65091ea65caeaa2059ee0f8e5a00e1 5431287 main/binary-amd64/Packages
 a3ba72d0b41c1517422ff2b982455db1 1422935 main/binary-amd64/Packages.gz
 6e8bf3a6440d38bb57959b4c19d096c4 121 main/binary-amd64/Release
 b552b11e559995233c7431c6007ab5fe 5281964 main/binary-arm64/Packages
 7f23b7d4afe02ad57bed496bc7be38a0 1386999 main/binary-arm64/Packages.gz
root@99488ea50755:/# lz4 /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_main_binary-amd64_Packages.lz4 -c | md5sum
bash: lz4: command not found
d41d8cd98f00b204e9800998ecf8427e  -
root@99488ea50755:/# apt-get install lz4
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  lz4
0 upgraded, 1 newly installed, 0 to remove and 3 not upgraded.
Need to get 90.0 kB of archives.
After this operation, 236 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu jammy/main amd64 lz4 amd64 1.9.3-2build2 [90.0 kB]
Fetched 90.0 kB in 0s (201 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package lz4.
(Reading database ... 39402 files and directories currently installed.)
Preparing to unpack .../lz4_1.9.3-2build2_amd64.deb ...
Unpacking lz4 (1.9.3-2build2) ...
Setting up lz4 (1.9.3-2build2) ...
root@99488ea50755:/# lz4 /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_main_binary-amd64_Packages.lz4 -c | md5sum
ec65091ea65caeaa2059ee0f8e5a00e1  -
root@99488ea50755:/# lz4 /var/lib/apt/lists/packages.ros.org_ros2_ubuntu_dists_jammy_main_binary-amd64_Packages.lz4 -c | grep "Package: ros-iron-image-transport-plugins" -A 20
Package: ros-iron-image-transport-plugins
Version: 3.1.0-1jammy.20231206.072142
Architecture: amd64
Maintainer: Kenji Brameld <[email protected]>
Installed-Size: 42
Depends: ros-iron-compressed-depth-image-transport, ros-iron-compressed-image-transport, ros-iron-theora-image-transport, ros-iron-ros-workspace
Homepage: http://www.ros.org/wiki/image_transport_plugins
Priority: optional
Section: misc
Filename: pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231206.072142_amd64.deb
Size: 6402
SHA256: 4b492f8ea49c1e0eb2c2a5d9fc59d57e36510978869c97ff39d4810d47d9835a
SHA1: 97225693f419fba026a7309aa82b9483f0efec4c
MD5sum: a987c88dcad58def4039976bdc5b1c1f
Description: A set of plugins for publishing and subscribing to sensor_msgs/Image topics in representations other than raw pixel data.
 For example, for viewing a stream of images off-robot, a video codec will give much lower bandwidth and latency. For low frame rate tranport of high-definition images, you might prefer sending them as JPEG or PNG-compressed form.

Package: ros-iron-image-view
Version: 3.0.1-3jammy.20231206.071211
Architecture: amd64
Maintainer: Vincent Rabaud <[email protected]>

• This starts with a base image.
• Updates the apt cache from the main repository
• Checks what version is expected to be installed, confirming December build, 20231206
• Looks at the apt cache and shows the latest Release
• Confirm that the cached Release file version matches the md5sum of amd64 binary ec65091ea65caeaa2059ee0f8e5a00e1
• Looks inside the file and find what the version listed in that file is the 20231206 build. And it points to pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231206.072142_amd64.deb which adding the repo aliases to the valid url http://packages.ros.org/ros2/ubuntu/pool/main/r/ros-iron-image-transport-plugins/ros-iron-image-transport-plugins_3.1.0-1jammy.20231206.072142_amd64.deb