Public Network Support

Add public network support to CephFS.  This patch also
adds in support for ipv6 and juju network spaces.

Closes-Bug: 1659338
Change-Id: Ibfb6377f5831f26da302308818c093c9d7e715dc

src/config.yaml

@@ -30,3 +30,23 @@ options:
     default: False
     description: |
       If set to True, supporting services will log to syslog.
+  ceph-public-network:
+    type: string
+    default:
+    description: |
+      The IP address and netmask of the public (front-side) network (e.g.,
+      192.168.0.0/24).
+      If multiple networks are to be used, a space-delimited list of a.b.c.d/x
+      can be provided.
+  prefer-ipv6:
+    type: boolean
+    default: False
+    description: |
+      If True enables IPv6 support. The charm will expect network interfaces
+      to be configured with an IPv6 address. If set to False (default) IPv4
+      is expected.
+
+      NOTE: these charms do not currently support IPv6 privacy extension. In
+      order for this charm to function correctly, the privacy extension must be
+      disabled and a non-temporary address must be configured/available on
+      your network interface.

src/metadata.yaml

@@ -16,3 +16,5 @@ subordinate: false
 requires:
   ceph-mds:
     interface: ceph-mds
+extra-bindings:
+  public:

src/reactive/ceph_fs.py

@@ -18,19 +18,27 @@ import subprocess
 
 from charms.reactive import when, when_not, set_state
 from charmhelpers.core.hookenv import (
-    application_version_set, config, log, ERROR)
+    application_version_set, config, log, ERROR, cached, DEBUG, unit_get,
+    network_get_primary_address,
+    status_set)
 from charmhelpers.core.host import service_restart
 from charmhelpers.contrib.network.ip import (
-    get_address_in_network
-)
+    get_address_in_network,
+    get_ipv6_addr)
+
 from charmhelpers.fetch import (
     get_upstream_version,
-)
-
+    apt_install, filter_installed_packages)
 import jinja2
 
 from charms.apt import queue_install
 
+try:
+    import dns.resolver
+except ImportError:
+    apt_install(filter_installed_packages(['python-dnspython']),
+                fatal=True)
+    import dns.resolver
 TEMPLATES_DIR = 'templates'
 VERSION_PACKAGE = 'ceph-common'
 
@@ -76,6 +84,7 @@ def config_changed(ceph_client):
         os.makedirs(key_path)
     cephx_key = os.path.join(key_path,
                              'keyring')
+
     ceph_context = {
         'fsid': ceph_client.fsid(),
         'auth_supported': ceph_client.auth(),
@@ -86,6 +95,15 @@ def config_changed(ceph_client):
         'mds_name': socket.gethostname(),
     }
 
+    networks = get_networks('ceph-public-network')
+    if networks:
+        ceph_context['ceph_public_network'] = ', '.join(networks)
+    elif config('prefer-ipv6'):
+        dynamic_ipv6_address = get_ipv6_addr()[0]
+        ceph_context['public_addr'] = dynamic_ipv6_address
+    else:
+        ceph_context['public_addr'] = get_public_addr()
+
     try:
         with open(charm_ceph_conf, 'w') as ceph_conf:
             ceph_conf.write(render_template('ceph.conf', ceph_context))
@@ -115,3 +133,59 @@ def get_networks(config_opt='ceph-public-network'):
         return [n for n in networks if get_address_in_network(n)]
 
     return []
+
+
+@cached
+def get_public_addr():
+    if config('ceph-public-network'):
+        return get_network_addrs('ceph-public-network')[0]
+
+    try:
+        return network_get_primary_address('public')
+    except NotImplementedError:
+        log("network-get not supported", DEBUG)
+
+    return get_host_ip()
+
+
+@cached
+def get_host_ip(hostname=None):
+    if config('prefer-ipv6'):
+        return get_ipv6_addr()[0]
+
+    hostname = hostname or unit_get('private-address')
+    try:
+        # Test to see if already an IPv4 address
+        socket.inet_aton(hostname)
+        return hostname
+    except socket.error:
+        # This may throw an NXDOMAIN exception; in which case
+        # things are badly broken so just let it kill the hook
+        answers = dns.resolver.query(hostname, 'A')
+        if answers:
+            return answers[0].address
+
+
+def get_network_addrs(config_opt):
+    """Get all configured public networks addresses.
+
+    If public network(s) are provided, go through them and return the
+    addresses we have configured on any of those networks.
+    """
+    addrs = []
+    networks = config(config_opt)
+    if networks:
+        networks = networks.split()
+        addrs = [get_address_in_network(n) for n in networks]
+        addrs = [a for a in addrs if a]
+
+    if not addrs:
+        if networks:
+            msg = ("Could not find an address on any of '%s' - resolve this "
+                   "error to retry" % networks)
+            status_set('blocked', msg)
+            raise Exception(msg)
+        else:
+            return [get_host_ip()]
+
+    return addrs

src/templates/ceph.conf

@@ -14,6 +14,13 @@ mon cluster log to syslog = {{ use_syslog }}
 debug mon = {{ loglevel }}/5
 debug osd = {{ loglevel }}/5
 
+{% if ceph_public_network %}
+public network = {{ ceph_public_network }}
+{%- endif %}
+{%- if public_addr %}
+public addr = {{ public_addr }}
+{%- endif %}
+
 [client]
 log file = /var/log/ceph.log