Make sanity checks for nfsboot deployments run earlier

Move some code to the '.check' extension to verify that the deployment
can happen *before* spending 5 minutes unpacking and configuring the
rootfs.

This is not a perfect solution yet because when multiple systems are
being deployed in a cluster, we do not check all systems and then
deploy them all. Instead, we check one, then deploy it, then check the
second, etc.

1 files changed, 66 insertions, 0 deletions

diff --git a/nfsboot.check b/nfsboot.check
index 092a1df7..e240dd72 100755
--- a/nfsboot.check
+++ b/nfsboot.check
@@ -17,18 +17,84 @@
 '''Preparatory checks for Morph 'nfsboot' write extension'''
 
 import cliapp
+import os
 
 import morphlib.writeexts
 
 
 class NFSBootCheckExtension(morphlib.writeexts.WriteExtension):
+
+    _nfsboot_root = '/srv/nfsboot'
+
     def process_args(self, args):
         if len(args) != 1:
             raise cliapp.AppException('Wrong number of command line args')
 
+        location = args[0]
+
         upgrade = self.get_environment_boolean('UPGRADE')
         if upgrade:
             raise cliapp.AppException(
                 'Upgrading is not currently supported for NFS deployments.')
 
+        hostname = os.environ.get('HOSTNAME', None)
+        if hostname is None:
+            raise cliapp.AppException('You must specify a HOSTNAME.')
+        if hostname == 'baserock':
+            raise cliapp.AppException('It is forbidden to nfsboot a system '
+                                      'with hostname "%s"' % hostname)
+
+        self.test_good_server(location)
+
+        version_label = os.getenv('VERSION_LABEL', 'factory')
+        versioned_root = os.path.join(self._nfsboot_root, hostname, 'systems',
+                                      version_label)
+        if self.version_exists(versioned_root, location):
+            raise cliapp.AppException(
+                'Root file system for host %s (version %s) already exists on '
+                'the NFS server %s. Deployment aborted.' % (hostname,
+                version_label, location))
+
+    def test_good_server(self, server):
+        # Can be ssh'ed into
+        try:
+            cliapp.ssh_runcmd('root@%s' % server, ['true'])
+        except cliapp.AppException:
+            raise cliapp.AppException('You are unable to ssh into server %s'
+                                      % server)
+
+        # Is an NFS server
+        try:
+            cliapp.ssh_runcmd(
+                'root@%s' % server, ['test', '-e', '/etc/exports'])
+        except cliapp.AppException:
+            raise cliapp.AppException('server %s is not an nfs server'
+                                      % server)
+        try:
+            cliapp.ssh_runcmd(
+                'root@%s' % server, ['systemctl', 'is-enabled',
+                                     'nfs-server.service'])
+
+        except cliapp.AppException:
+            raise cliapp.AppException('server %s does not control its '
+                                      'nfs server by systemd' % server)
+
+        # TFTP server exports /srv/nfsboot/tftp
+        try:
+            cliapp.ssh_runcmd(
+                'root@%s' % server, ['test' , '-d', '/srv/nfsboot/tftp'])
+        except cliapp.AppException:
+            raise cliapp.AppException('server %s does not export '
+                                      '/srv/nfsboot/tftp' % server)
+
+    def version_exists(self, versioned_root, location):
+        try:
+            cliapp.ssh_runcmd('root@%s' % location,
+                ['test', '-d', versioned_root])
+        except cliapp.AppException:
+            return False
+
+        return True
+
+
 NFSBootCheckExtension().run()