Remove support for older distros

Documentation/index.rst

@@ -39,6 +39,9 @@ image.
 Prerequisites
 =============
 
+The installation descriptions of prerequisites are for Ubuntu 22.04 and may
+differ when using a different Ubuntu version or Linux distribution.
+
 Software packages
 -----------------
 
@@ -319,22 +322,20 @@ in :file:`config.yaml.template`.
 
 .. describe:: Distro
 
-   Defines Linux distribution to be used to build Gramine in. This distro should
-   match the distro of the supplied Docker image; otherwise the results may be
-   unpredictable. Currently supported distros are Ubuntu 20.04, Ubuntu 21.04,
-   Ubuntu 22.04, Ubuntu 23.04, Debian 10, Debian 11, Debian 12, CentOS 8, CentOS
-   Stream 9, Red Hat Universal Base Image (UBI) 8, Red Hat Universal Base Image
-   (UBI) 9, Red Hat Universal Base Image (UBI) 8 minimal, Red Hat Universal Base Image
-   9 minimal and SUSE Linux Enterprise Server 15.
+   Defines Linux distribution to be used to build Gramine in. This distro
+   should match the distro of the supplied Docker image; otherwise the
+   results may be unpredictable. Currently supported distros are Ubuntu
+   22.04, Ubuntu 24.04, Debian 11, Debian 12, CentOS Stream 9, Red Hat Universal Base
+   Image (UBI) 9, Red Hat Universal Base Image (UBI) 9 minimal, and SUSE
+   Linux Enterprise Server 15.
 
    Default value is ``auto`` which means GSC automatically detects the distro
    of the supplied Docker image. Users also have the option to provide one of
    the supported distros mentioned above.
 
    .. warning::
       Please register and subscribe your host RHEL system to the Red Hat
-      Customer Portal to use Red Hat Universal Base Image (UBI) 8, Red Hat
-      Universal Base Image (UBI) 9, UBI8-minimal and UBI9-minimal distros.
+      Customer Portal to use Red Hat Universal Base Image (UBI) 9 and UBI9-minimal distros.
 
 .. describe:: Registry
 

config.yaml.template

@@ -4,12 +4,11 @@
 # which is recommended, you don't need to worry about the mismatch).
 #
 # Currently supported distros are:
-# - ubuntu:20.04, ubuntu:21.04, ubuntu:22.04, ubuntu:23.04
-# - debian:10, debian:11, debian:12
-# - centos:8
+# - ubuntu:22.04, ubuntu:24.04
+# - debian:11, debian:12
 # - quay.io/centos/centos:stream9
-# - redhat/ubi8:8.8, redhat/ubi9:9.4
-# - redhat/ubi8-minimal:8.8, redhat/ubi9-minimal:9.4
+# - redhat/ubi9:9.4
+# - redhat/ubi9-minimal:9.4
 # - registry.suse.com/suse/sle15:15.4
 
 # If Distro is set to "auto", GSC detects the distro automatically by examining the supplied

test/README.rst

@@ -30,11 +30,11 @@ below commands assume that you already created the GSC configuration file
 
    cd ..
 
-   docker build --tag ubuntu20.04-bash --file test/ubuntu20.04-bash.dockerfile .
+   docker build --tag ubuntu22.04-bash --file test/ubuntu22.04-bash.dockerfile .
 
-   ./gsc build --insecure-args ubuntu20.04-bash test/ubuntu20.04-bash.manifest
-   ./gsc sign-image ubuntu20.04-bash enclave-key.pem
-   ./gsc info-image gsc-ubuntu20.04-bash
+   ./gsc build --insecure-args ubuntu22.04-bash test/ubuntu22.04-bash.manifest
+   ./gsc sign-image ubuntu22.04-bash enclave-key.pem
+   ./gsc info-image gsc-ubuntu22.04-bash
 
 Test the graminized Docker image (change ``--device=/dev/sgx_enclave`` to your
 version of the Intel SGX driver if needed):
@@ -43,4 +43,4 @@ version of the Intel SGX driver if needed):
 
    docker run --device=/dev/sgx_enclave \
       -v /var/run/aesmd/aesm.socket:/var/run/aesmd/aesm.socket \
-      gsc-ubuntu20.04-bash -c ls
+      gsc-ubuntu22.04-bash -c ls

test/ubuntu20.04-bash.dockerfile → test/ubuntu22.04-bash.dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:22.04
 
 RUN apt-get update