Support CentOS kernels

Resolves #8

tools/qemu-centos-img/7/Dockerfile

@@ -1,4 +1,4 @@
-# Copyright 2018 Mikhail Klementev. All rights reserved.
+# Copyright 2019 Mikhail Klementev. All rights reserved.
 # Use of this source code is governed by a AGPLv3 license
 # (or later) that can be found in the LICENSE file.
 #
@@ -7,11 +7,13 @@
 #     $ docker build -t gen-centos7-image .
 #     $ docker run --privileged -v $(pwd):/shared -t gen-centos7-image
 #
-# centos7.img will be created in current directory. You can change $(pwd) to
-# different directory to use different destination for image.
+# out_of_tree_centos_7.img will be created in current directory.
+# You can change $(pwd) to different directory to use different destination
+# for image.
 #
 FROM centos:7
 
+RUN yum -y update
 RUN yum -y groupinstall "Development Tools"
 RUN yum -y install qemu-img e2fsprogs
 
@@ -26,7 +28,7 @@ RUN yum --installroot=$TMPDIR \
         --releasever=7 \
         --disablerepo='*' \
         --enablerepo=base \
-        -y install openssh-server
+        -y install openssh-server openssh-clients
 
 RUN chroot $TMPDIR /bin/sh -c 'useradd -m user'
 RUN sed -i 's/root:\*:/root::/' $TMPDIR/etc/shadow
@@ -37,13 +39,11 @@ RUN sed -i '/PermitRootLogin/d' $TMPDIR/etc/ssh/sshd_config
 RUN echo PermitRootLogin yes >> $TMPDIR/etc/ssh/sshd_config
 
 # network workaround
-# FIXME kernel module compatibility issues
 RUN chmod +x $TMPDIR/etc/rc.local
-RUN echo 'find /lib/modules | grep e1000.ko | xargs insmod -f' >> $TMPDIR/etc/rc.local
 RUN echo 'dhclient' >> $TMPDIR/etc/rc.local
 
 ENV IMAGEDIR=/tmp/image
-ENV IMAGE=/shared/centos7.img
+ENV IMAGE=/shared/out_of_tree_centos_7.img
 
 RUN mkdir $IMAGEDIR