c7testvm: Script to create a CentOS 7 test VM

This script creates a new virtual machine using `virt-install`. It then starts
an HTTP server to serve a kickstart configuration file to the new VM, which is
used to automatically install CentOS.

c7testvm.py

@@ -0,0 +1,226 @@
+#!/usr/bin/env python
+import argparse
+import binascii
+import http.server
+import os
+import random
+import socket
+import string
+import subprocess
+import time
+
+
+HTTP_PROXY = 'caithe.pyrocufflink.jazz:3128'
+PORT_RANGE = (10000, 65535)
+REPO_URL = 'http://mirror.centos.org/centos/7/os/x86_64'
+
+
+KICKSTART = string.Template('''\
+text
+install
+url --url=http://mirror.centos.org/centos/7/os/x86_64
+repo --name=updates --baseurl=http://mirror.centos.org/centos/7/updates/x86_64
+repo --name=extras --baseurl=http://mirror.centos.org/centos/7/extras/x86_64
+lang en_US.UTF-8
+keyboard us
+timezone --utc UTC
+rootpw --iscrypted x
+shutdown
+
+bootloader --location=mbr
+clearpart --all --initlabel
+autopart --type=lvm
+
+network --hostname=${hostname}
+
+%packages --nocore
+@core --nodefaults
+-biosdevname
+-btrfs-progs
+-firewalld
+-iprutils
+-irqbalance
+-kexec-tools
+-man-db
+-parted
+-plymouth
+-teamd
+-tuned
+avahi
+qemu-guest-agent
+%end
+
+%addon com_redhat_kdump --disable
+%end
+
+%post
+install -d /root/.ssh
+cat > /root/.ssh/authorized_keys <<EOF
+${ssh_pubkey}
+EOF
+sed 's/use-ipv6=.*/use-ipv6=yes/' /etc/avahi/avahi-daemon.conf
+%end
+''')
+
+
+class KickstartHTTPServer(http.server.HTTPServer):
+
+    address_family = socket.AF_INET6
+
+    def __init__(self, kickstart):
+        port = random.randint(*PORT_RANGE)
+        super(KickstartHTTPServer, self).__init__(
+            server_address=('::', port),
+            RequestHandlerClass=KickstartHTTPRequestHandler,
+        )
+        self.kickstart = kickstart
+
+
+class KickstartHTTPRequestHandler(http.server.BaseHTTPRequestHandler):
+
+    def do_GET(self):
+        self.do_HEAD()
+        self.wfile.write(self.server.kickstart)
+
+    def do_HEAD(self):
+        self.send_response(200)
+        self.send_header('Content-Type', 'text/plain; charset=utf-8')
+        self.send_header('Content-Length', str(len(self.server.kickstart)))
+        self.end_headers()
+
+
+def get_server_name():
+    tries = [
+        (socket.AF_INET6, '2001:db8::1'),
+        (socket.AF_INET, '203.0.113.1'),
+    ]
+    addr = None
+    for af, remote in tries:
+        s = socket.socket(af, socket.SOCK_DGRAM)
+        try:
+            s.connect((remote, 0))
+            addr = s.getsockname()[0]
+        except:
+            pass
+        finally:
+            s.close()
+    if addr is None:
+        try:
+            addr = socket.gethostbyname(socket.gethostname())
+        except:
+            return socket.gethostname()
+    try:
+        return socket.gethostbyaddr(addr)[0]
+    except:
+        return addr
+
+
+def get_ssh_pubkey():
+    dirname = os.path.expanduser('~/.ssh')
+    for t in ('ed25519', 'rsa', 'ecdsa'):
+        try:
+            with open(os.path.join(dirname, 'id_{}.pub'.format(t))) as f:
+                return f.read()
+        except OSError:
+            continue
+    return ''
+
+
+def virt_install(args):
+    yield 'virt-install'
+    for key, value in args.items():
+        yield '--{}'.format(key)
+        if value is not None:
+            yield str(value)
+
+
+def wait_for_host(host, port, timeout=300):
+    deadline = time.time() + timeout
+    while time.time() < deadline:
+        try:
+            sock = socket.create_connection((host, port))
+        except OSError:
+            pass
+        else:
+            sock.close()
+            return True
+    return False
+
+
+def parse_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--ram', type=int, default=1024)
+    parser.add_argument('--vcpus', type=int, default=2)
+    parser.add_argument('--cpu', default='host')
+    parser.add_argument('--location', default=REPO_URL)
+    parser.add_argument('--disk-pool', default='default')
+    parser.add_argument('--disk-size', type=int, default=6)
+    parser.add_argument('--network', default='bridge=br0')
+    parser.add_argument('--sound', default='none')
+    parser.add_argument('--server-name')
+    parser.add_argument('--ip', default='dhcp')
+    parser.add_argument('--ssh-key')
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+
+    name = 'C7-{}'.format(binascii.hexlify(os.urandom(3)).decode())
+    hostname = '{}.local'.format(name.lower())
+
+    if args.ssh_key is None:
+        ssh_pubkey = get_ssh_pubkey()
+    else:
+        ssh_pubkey = args.ssh_key
+
+    kickstart = KICKSTART.substitute(
+        hostname=hostname,
+        ssh_pubkey=ssh_pubkey,
+    )
+
+    httpd = KickstartHTTPServer(kickstart.encode('utf-8'))
+
+    kcmdline = 'ip={ip} proxy={proxy} ks=http://{server}:{port}/'.format(
+        ip=args.ip,
+        proxy=HTTP_PROXY,
+        server=args.server_name or get_server_name(),
+        port=httpd.server_port,
+    )
+
+    cmd = list(virt_install({
+        'name': name,
+        'ram': args.ram,
+        'vcpus': args.vcpus,
+        'cpu': args.cpu,
+        'location': args.location,
+        'extra-args': kcmdline,
+        'os-type': 'linux',
+        'os-variant': 'rhel7',
+        'disk': 'pool={pool},size={size}'.format(
+            pool=args.disk_pool,
+            size=args.disk_size,
+        ),
+        'network': args.network,
+        'sound': args.sound,
+        'redirdev': 'none',
+        'noautoconsole': None,
+        'wait': -1,
+    }))
+    env = os.environ.copy()
+    env['http_proxy'] = HTTP_PROXY
+    p = subprocess.Popen(cmd, env=env)
+    httpd.handle_request()
+    httpd.server_close()
+    p.wait()
+    print('Waiting for host to come up...')
+    if wait_for_host(hostname, 22):
+        os.execlp('ssh', 'ssh', '-oStrictHostKeyChecking=no',
+                  'root@{}'.format(hostname))
+    else:
+        sys.stderr.write('Timed out waiting for {}\n'.format(hostname))
+        raise SystemExit(1)
+
+
+if __name__ == '__main__':
+    main()