diff --git a/.github/workflows/q2q-candidate-upgrade.yml b/.github/workflows/q2q-candidate-upgrade.yml
index 9963d7ec..fbf00651 100644
--- a/.github/workflows/q2q-candidate-upgrade.yml
+++ b/.github/workflows/q2q-candidate-upgrade.yml
@@ -58,5 +58,8 @@ jobs:
     - name: Wait until 3 OSDs are up
       run:  ~/actionutils.sh headexec wait_for_osds 3
 
+    - name: Verify config
+      run: ~/actionutils.sh test_ceph_conf
+
     - name: Exercise RGW again
       run: ~/actionutils.sh headexec testrgw
diff --git a/.github/workflows/q2r-candidate-upgrade.yaml b/.github/workflows/q2r-candidate-upgrade.yaml
index c06b67da..d2a08c57 100644
--- a/.github/workflows/q2r-candidate-upgrade.yaml
+++ b/.github/workflows/q2r-candidate-upgrade.yaml
@@ -58,5 +58,8 @@ jobs:
     - name: Wait until 3 OSDs are up
       run:  ~/actionutils.sh headexec wait_for_osds 3
 
+    - name: Verify config
+      run: ~/actionutils.sh test_ceph_conf
+
     - name: Exercise RGW again
       run: ~/actionutils.sh headexec testrgw
diff --git a/.github/workflows/r2r-candidate-upgrade.yaml b/.github/workflows/r2r-candidate-upgrade.yaml
index f00f9c3e..c1f94b1c 100644
--- a/.github/workflows/r2r-candidate-upgrade.yaml
+++ b/.github/workflows/r2r-candidate-upgrade.yaml
@@ -58,5 +58,8 @@ jobs:
     - name: Wait until 3 OSDs are up
       run:  ~/actionutils.sh headexec wait_for_osds 3
 
+    - name: Verify config
+      run: ~/actionutils.sh test_ceph_conf
+
     - name: Exercise RGW again
       run: ~/actionutils.sh headexec testrgw
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6cbbdd32..8d10a426 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -255,6 +255,9 @@ jobs:
     - name: Setup cluster
       run: ~/actionutils.sh cluster_nodes custom
 
+    - name: Verify config
+      run: ~/actionutils.sh test_ceph_conf
+
     - name: Add 2 OSDs
       run: |
         for c in node-wrk1 node-wrk2 ; do
@@ -489,4 +492,3 @@ jobs:
 
     - name: Exercise RGW again
       run: ~/actionutils.sh headexec testrgw
-      
diff --git a/microceph/ceph/config.go b/microceph/ceph/config.go
index 82859024..eabc547a 100644
--- a/microceph/ceph/config.go
+++ b/microceph/ceph/config.go
@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/canonical/microceph/microceph/interfaces"
+	"net"
 	"os"
 	"path/filepath"
 	"strings"
@@ -162,36 +163,98 @@ func ListConfigs() (types.Configs, error) {
 	return configs, nil
 }
 
-// updates the ceph config file.
-func UpdateConfig(s interfaces.StateInterface) error {
-	confPath := filepath.Join(os.Getenv("SNAP_DATA"), "conf")
-	runPath := filepath.Join(os.Getenv("SNAP_DATA"), "run")
+// backwardCompatPubnet ensures that the public_network is set in the database
+// this is a backward-compat shim to accomodate older versions of microceph
+// which will ensure that the public_network is set in the database
+func backwardCompatPubnet(s interfaces.StateInterface) error {
+	config, err := getConfigDb(s)
+	if err != nil {
+		return fmt.Errorf("failed to get config from db: %w", err)
+	}
 
-	// Get the configuration and servers.
+	// do we have a public_network configured?
+	// if it is unset, the below will evaluate to the empty string
+	// and subsequently fail the net.ParseCIDR check
+	pubNet := config["public_network"]
+	_, _, err = net.ParseCIDR(pubNet)
+	if err != nil {
+		// get public network from default address
+		pubNet, err = common.Network.FindNetworkAddress(s.ClusterState().Address().Hostname())
+		if err != nil {
+			return fmt.Errorf("failed to locate public network: %w", err)
+		}
+		// update the database
+		err = s.ClusterState().Database.Transaction(s.ClusterState().Context, func(ctx context.Context, tx *sql.Tx) error {
+			_, err = database.CreateConfigItem(ctx, tx, database.ConfigItem{Key: "public_network", Value: pubNet})
+			if err != nil {
+				return fmt.Errorf("failed to record public_network: %w", err)
+			}
+			return nil
+		})
+	}
+
+	return nil
+}
+
+// backwardCompatMonitors retrieves monitor addresses from the node list and returns that
+// this a backward-compat shim to accomodate older versions of microceph
+func backwardCompatMonitors(s interfaces.StateInterface) ([]string, error) {
 	var err error
-	var configItems []database.ConfigItem
+	var monitors []database.Service
+	serviceName := "mon"
 
 	err = s.ClusterState().Database.Transaction(s.ClusterState().Context, func(ctx context.Context, tx *sql.Tx) error {
-		configItems, err = database.GetConfigItems(ctx, tx)
+		monitors, err = database.GetServices(ctx, tx, database.ServiceFilter{Service: &serviceName})
 		if err != nil {
 			return err
 		}
-
 		return nil
 	})
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	config := map[string]string{}
-	for _, item := range configItems {
-		config[item.Key] = item.Value
+	monitorAddresses := make([]string, len(monitors))
+	remotes := s.ClusterState().Remotes().RemotesByName()
+	for i, monitor := range monitors {
+		remote, ok := remotes[monitor.Member]
+		if !ok {
+			continue
+		}
+		monitorAddresses[i] = remote.Address.Addr().String()
+	}
+	return monitorAddresses, nil
+}
+
+// UpdateConfig updates the ceph.conf file with the current configuration.
+func UpdateConfig(s interfaces.StateInterface) error {
+	confPath := filepath.Join(os.Getenv("SNAP_DATA"), "conf")
+	runPath := filepath.Join(os.Getenv("SNAP_DATA"), "run")
+
+	err := backwardCompatPubnet(s)
+	if err != nil {
+		return fmt.Errorf("failed to ensure backward compat: %w", err)
+	}
+
+	config, err := getConfigDb(s)
+	if err != nil {
+		return fmt.Errorf("failed to get config db: %w", err)
 	}
 
 	// REF: https://docs.ceph.com/en/quincy/rados/configuration/network-config-ref/#ceph-daemons
 	// The mon host configuration option only needs to be sufficiently up to date such that a
 	// client can reach one monitor that is currently online.
 	monitorAddresses := getMonitorAddresses(config)
+
+	// backward compat: if no mon hosts found, get them from the node addresses but don't
+	// insert into db, as the join logic will take care of that.
+	if len(monitorAddresses) == 0 {
+		monitorAddresses, err = backwardCompatMonitors(s)
+		if err != nil {
+			return fmt.Errorf("failed to get monitor addresses: %w", err)
+		}
+	}
+
 	conf := newCephConfig(confPath)
 
 	// Check if host has IP address on the configured public network.
@@ -199,6 +262,7 @@ func UpdateConfig(s interfaces.StateInterface) error {
 	if err != nil {
 		return fmt.Errorf("failed to locate IP on public network %s: %w", config["public_network"], err)
 	}
+
 	clientConfig, err := GetClientConfigForHost(s, s.ClusterState().Name())
 	if err != nil {
 		logger.Errorf("Failed to pull Client Configurations: %v", err)
@@ -225,6 +289,7 @@ func UpdateConfig(s interfaces.StateInterface) error {
 	if err != nil {
 		return fmt.Errorf("couldn't render ceph.conf: %w", err)
 	}
+	logger.Debugf("updated ceph.conf: %v", conf.GetPath())
 
 	// Generate ceph.client.admin.keyring
 	keyring := newCephKeyring(confPath, "ceph.keyring")
@@ -242,6 +307,30 @@ func UpdateConfig(s interfaces.StateInterface) error {
 	return nil
 }
 
+// getConfigDb retrieves the configuration from the database.
+func getConfigDb(s interfaces.StateInterface) (map[string]string, error) {
+	var err error
+	var configItems []database.ConfigItem
+
+	err = s.ClusterState().Database.Transaction(s.ClusterState().Context, func(ctx context.Context, tx *sql.Tx) error {
+		configItems, err = database.GetConfigItems(ctx, tx)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	config := map[string]string{}
+	for _, item := range configItems {
+		config[item.Key] = item.Value
+	}
+	return config, nil
+}
+
 // getMonitorAddresses scans a provided config key/value map and returns a list of mon hosts found.
 func getMonitorAddresses(configs map[string]string) []string {
 	monHosts := []string{}
diff --git a/microceph/ceph/start.go b/microceph/ceph/start.go
index aac8ec6b..6af259c6 100644
--- a/microceph/ceph/start.go
+++ b/microceph/ceph/start.go
@@ -3,6 +3,7 @@ package ceph
 import (
 	"context"
 	"database/sql"
+	"github.com/canonical/lxd/shared/logger"
 	"github.com/canonical/microceph/microceph/interfaces"
 	"reflect"
 	"time"
@@ -19,6 +20,7 @@ func Start(s interfaces.StateInterface) error {
 		for {
 			// Check that the database is ready.
 			if !s.ClusterState().Database.IsOpen() {
+				logger.Debug("start: database not ready, waiting...")
 				time.Sleep(10 * time.Second)
 				continue
 			}
@@ -39,26 +41,28 @@ func Start(s interfaces.StateInterface) error {
 				return nil
 			})
 			if err != nil {
+				logger.Warnf("start: failed to fetch monitors, retrying: %v", err)
 				time.Sleep(10 * time.Second)
 				continue
 			}
 
 			// Compare to the previous list.
 			if reflect.DeepEqual(oldMonitors, monitors) {
+				logger.Debugf("start: monitors unchanged, sleeping: %v", monitors)
 				time.Sleep(time.Minute)
 				continue
 			}
 
 			err = UpdateConfig(s)
 			if err != nil {
+				logger.Errorf("start: failed to update config, retrying: %v", err)
 				time.Sleep(10 * time.Second)
 				continue
 			}
-
+			logger.Debug("start: updated config, sleeping")
 			oldMonitors = monitors
 			time.Sleep(time.Minute)
 		}
-
 	}()
 
 	return nil
diff --git a/tests/scripts/actionutils.sh b/tests/scripts/actionutils.sh
index 78302f88..b49d3b84 100755
--- a/tests/scripts/actionutils.sh
+++ b/tests/scripts/actionutils.sh
@@ -388,6 +388,31 @@ function test_migration() {
     return -1
 }
 
+function test_ceph_conf() {
+    set -uex
+    for n in $( lxc ls -c n --format csv ); do
+        echo "checking node $n"
+        lxc exec $n -- sh <<'EOF'
+# Test: configured rundir must be current
+current=$( realpath /var/snap/microceph/current )
+rundir=$( cat /var/snap/microceph/current/conf/ceph.conf | awk '/run dir/{ print $4 }' )
+p=$( dirname $rundir )
+if [ $p != $current ]; then
+    echo "Error: snap data dir $current, configured run dir: $rundir"
+    cat /var/snap/microceph/current/conf/ceph.conf
+    exit -1
+fi
+
+# Test: must contain public_network
+if ! grep -q public_net /var/snap/microceph/current/conf/ceph.conf ; then
+    echo "Error: didn't find public_net in ceph.conf"
+    cat /var/snap/microceph/current/conf/ceph.conf
+    exit -1
+fi
+EOF
+    done
+}
+
 function headexec() {
     local run="${1?missing}"
     shift