Update the RHEL 7 Dockerfile setup for building on Rust 1.74

Author: chriskrycho

ci/build-linux.sh

@@ -3,7 +3,8 @@
 set -e
 
 # Activate the upgraded versions of GCC and binutils
-source /opt/rh/devtoolset-2/enable
+# See https://linux.web.cern.ch/centos7/docs/softwarecollections/#inst
+source /opt/rh/devtoolset-8/enable
 
 echo "Building Volta"
 

ci/docker/Dockerfile

@@ -1,19 +1,16 @@
-FROM cern/slc6-base
+FROM cern/cc7-base
 
 # This repo file references a URL that is no longer valid. It also isn't used by the build
 # toolchain, so we can safely remove it entirely
 RUN rm /etc/yum.repos.d/epel.repo
 
+# https://linux.web.cern.ch/centos7/docs/softwarecollections/#inst
 # Tools needed for the build and setup process
 RUN yum -y install wget tar
 # Fetch the repo information for the devtoolset repo
-RUN wget -O /etc/yum.repos.d/slc6-devtoolset.repo http://linuxsoft.cern.ch/cern/devtoolset/slc6-devtoolset.repo
-# Install more recent GCC and binutils, to allow us to compile 
-RUN yum -y install devtoolset-2-gcc devtoolset-2-binutils
+RUN yum install -y centos-release-scl
+# Install more recent GCC and binutils, to allow us to compile
+RUN yum install -y devtoolset-8
 
-# Install Rust toolchain (need to do this manually since current rustup requires a more recent
-# glibc version than is available on RHEL/CentOS 6)
-RUN curl https://static.rust-lang.org/rustup/archive/1.25.1/x86_64-unknown-linux-gnu/rustup-init -sSf -o ~/rustup-init
-RUN chmod +x ~/rustup-init
-RUN ~/rustup-init -y --default-toolchain 1.63
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
 ENV PATH="/root/.cargo/bin:${PATH}"