Retry SSH keyscan command

Makefile

@@ -69,8 +69,8 @@ build/.%.done: docker/Dockerfile.%
 		-f build/docker/$*/Dockerfile.$* ./build/docker/$*
 	touch $@
 
-build/.flux.done: build/fluxd build/kubectl docker/ssh_config docker/kubeconfig docker/verify_known_hosts.sh
-build/.helm-operator.done: build/helm-operator build/kubectl build/helm docker/ssh_config docker/verify_known_hosts.sh docker/helm-repositories.yaml
+build/.flux.done: build/fluxd build/kubectl docker/ssh_config docker/kubeconfig docker/verify_known_hosts.sh docker/known_hosts.sh
+build/.helm-operator.done: build/helm-operator build/kubectl build/helm docker/ssh_config docker/verify_known_hosts.sh docker/known_hosts.sh docker/helm-repositories.yaml
 
 build/fluxd: $(FLUXD_DEPS)
 build/fluxd: cmd/fluxd/*.go

docker/Dockerfile.flux

@@ -7,9 +7,10 @@ RUN apk add --no-cache openssh ca-certificates tini 'git>=2.3.0' gnupg
 # Add git hosts to known hosts file so we can use
 # StrickHostKeyChecking with git+ssh
 ADD ./verify_known_hosts.sh /home/flux/verify_known_hosts.sh
-RUN ssh-keyscan github.com gitlab.com bitbucket.org ssh.dev.azure.com vs-ssh.visualstudio.com >> /etc/ssh/ssh_known_hosts && \
-    sh /home/flux/verify_known_hosts.sh /etc/ssh/ssh_known_hosts && \
-    rm /home/flux/verify_known_hosts.sh
+ADD ./known_hosts.sh /home/flux/known_hosts.sh
+RUN sh /home/flux/known_hosts.sh /etc/ssh/ssh_known_hosts && \
+    rm /home/flux/verify_known_hosts.sh && \
+    rm /home/flux/known_hosts.sh
 
 # Add default SSH config, which points at the private key we'll mount
 COPY ./ssh_config /etc/ssh/ssh_config

docker/Dockerfile.helm-operator

@@ -7,9 +7,10 @@ RUN apk add --no-cache openssh ca-certificates tini 'git>=2.3.0'
 # Add git hosts to known hosts file so we can use
 # StrickHostKeyChecking with git+ssh
 ADD ./verify_known_hosts.sh /home/flux/verify_known_hosts.sh
-RUN ssh-keyscan github.com gitlab.com bitbucket.org ssh.dev.azure.com vs-ssh.visualstudio.com >> /etc/ssh/ssh_known_hosts && \
-    sh /home/flux/verify_known_hosts.sh /etc/ssh/ssh_known_hosts && \
-    rm /home/flux/verify_known_hosts.sh
+ADD ./known_hosts.sh /home/flux/known_hosts.sh
+RUN sh /home/flux/known_hosts.sh /etc/ssh/ssh_known_hosts && \
+    rm /home/flux/verify_known_hosts.sh && \
+    rm /home/flux/known_hosts.sh
 
 # Add default SSH config, which points at the private key we'll mount
 COPY ./ssh_config /etc/ssh/ssh_config

docker/known_hosts.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+set -eu
+
+known_hosts_file=${1}
+known_hosts_file=${known_hosts_file:-/etc/ssh/ssh_known_hosts}
+
+retries=10
+count=0
+ok=false
+until ${ok}; do
+    ssh-keyscan github.com gitlab.com bitbucket.org ssh.dev.azure.com vs-ssh.visualstudio.com >> ${known_hosts_file} && \
+    sh /home/flux/verify_known_hosts.sh ${known_hosts_file} && ok=true || ok=false
+    sleep 2
+    count=$(($count + 1))
+    if [[ ${count} -eq ${retries} ]]; then
+        echo "No more retries left"
+        exit 1
+    fi
+done