Varnish container uses version 6.3.1.

container/Dockerfile.varnish

-FROM centos:centos7
-COPY varnishcache_varnish61.repo /etc/yum.repos.d/
-RUN yum install -y epel-release && yum update -y -q && \
-    yum -q makecache -y --disablerepo='*' --enablerepo='varnishcache_varnish61' && \
-    yum-config-manager --add-repo https://pkg.uplex.de/rpm/7/uplex-varnish/x86_64/ && \
-    yum install -y -q varnish-6.1.1 && \
-    yum install -y -q --nogpgcheck vmod-re2-1.6.1 && \
-    yum install -y -q --nogpgcheck vmod-selector-1.0.0 && \
-    yum clean all && rm -rf /var/cache/yum
+FROM centos:centos7.6.1810
+
+COPY varnishcache_varnish63.repo /etc/yum.repos.d/
+COPY uplex_varnish.repo /etc/yum.repos.d/
+
+# yum update with --exclude=shadow-utils because the cap_set_file
+# capability is needed to extract the RPM, and that fails in a
+# docker build.
+RUN yum install -y -q epel-release && yum -q makecache -y fast && \
+    yum update -y -q --exclude=shadow-utils && \
+    yum install -y -q varnish-6.3.1 && \
+    yum install -y -q --nogpgcheck vmod-re2-1.8.0 && \
+    yum install -y -q --nogpgcheck vmod-selector-1.3.1 && \
+    yum -q clean all && rm -rf /var/cache/yum && rm -rf /usr/share/man && \
+    rm -rf /usr/share/doc && rm /etc/varnish/*
+
 RUN /bin/mkdir /var/run/varnish
 COPY bogo_backend.vcl /etc/varnish/
 COPY ready.vcl /etc/varnish/
 COPY notavailable.vcl /etc/varnish
 COPY boot.vcl /etc/varnish
 COPY start.cli /etc/varnish
+
 COPY varnishd_exec.sh /
 RUN /bin/chmod 755 /varnishd_exec.sh
+
 ENV HTTP_PORT=80 PROTO=HTTP READY_PORT=8080 SECRET_PATH=/var/run/varnish \
     SECRET_FILE=_.secret ADMIN_PORT=6081
+
 ENTRYPOINT ["/varnishd_exec.sh"]

container/uplex_varnish.repo

+[uplex_varnish]
+name=pkg_uplex_de
+baseurl=https://pkg.uplex.de/rpm/7/uplex-varnish/$basearch
+repo_gpgcheck=0
+gpgcheck=0
+enabled=1
+sslverify=1
+sslcacert=/etc/pki/tls/certs/ca-bundle.crt
+metadata_expire=300

container/varnishcache_varnish61.repo → container/varnishcache_varnish63.repo

-[varnishcache_varnish61]
-name=varnishcache_varnish61
-baseurl=https://packagecloud.io/varnishcache/varnish61/el/7/$basearch
+[varnishcache_varnish63]
+name=varnishcache_varnish63
+baseurl=https://packagecloud.io/varnishcache/varnish63/el/7/$basearch
 repo_gpgcheck=1
 gpgcheck=0
 enabled=1
-gpgkey=https://packagecloud.io/varnishcache/varnish61/gpgkey
+gpgkey=https://packagecloud.io/varnishcache/varnish63/gpgkey
 sslverify=1
 sslcacert=/etc/pki/tls/certs/ca-bundle.crt
 metadata_expire=300
 
-[varnishcache_varnish61-source]
-name=varnishcache_varnish61-source
-baseurl=https://packagecloud.io/varnishcache/varnish61/el/7/SRPMS
+[varnishcache_varnish63-source]
+name=varnishcache_varnish63-source
+baseurl=https://packagecloud.io/varnishcache/varnish63/el/7/SRPMS
 repo_gpgcheck=1
 gpgcheck=0
 enabled=1
-gpgkey=https://packagecloud.io/varnishcache/varnish61/gpgkey
+gpgkey=https://packagecloud.io/varnishcache/varnish63/gpgkey
 sslverify=1
 sslcacert=/etc/pki/tls/certs/ca-bundle.crt
 metadata_expire=300

go.mod

 module code.uplex.de/uplex-varnish/k8s-ingress
 
 require (
-	code.uplex.de/uplex-varnish/varnishapi v0.0.0-20181209154204-43826850baae
+	code.uplex.de/uplex-varnish/varnishapi v0.0.0-20191205154529-31e610a4139d
 	github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff // indirect
 	github.com/google/go-cmp v0.3.0
 	github.com/googleapis/gnostic v0.2.0 // indirect

go.sum

 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.38.0/go.mod h1:990N+gfupTy94rShfmMCWGDn0LpTmnzTp2qbd1dvSRU=
-code.uplex.de/uplex-varnish/varnishapi v0.0.0-20181209154204-43826850baae h1:rV0/WL/NvJ8/TAQwmcSxFUyI5TVA5GM0KBXXfnWrsFY=
-code.uplex.de/uplex-varnish/varnishapi v0.0.0-20181209154204-43826850baae/go.mod h1:J0znUDkk1j5lNWKZZ6zfISZWbA2fXvsxCM+FpDUxG9g=
+code.uplex.de/uplex-varnish/varnishapi v0.0.0-20191205154529-31e610a4139d h1:W1qDaGvBh7aBY30jCGpnt4m9eSCwgczD8YFNqseq7Kg=
+code.uplex.de/uplex-varnish/varnishapi v0.0.0-20191205154529-31e610a4139d/go.mod h1:J0znUDkk1j5lNWKZZ6zfISZWbA2fXvsxCM+FpDUxG9g=
 github.com/Azure/go-autorest/autorest v0.9.0/go.mod h1:xyHB1BMZT0cuDHU7I0+g046+BFDTQ8rEZB0s4Yfa6bI=
 github.com/Azure/go-autorest/autorest/adal v0.5.0/go.mod h1:8Z9fGy2MpX0PvDjB1pEgQTmVqjGhiHBW7RJJEciWzS0=
 github.com/Azure/go-autorest/autorest/date v0.1.0/go.mod h1:plvfp3oPSKwf2DNjlBjWF/7vwR+cUD/ELuzDCXwHUVA=