Single node support (#319)

Adds basic single-node support.

This adds an initial question to `microcloud init` asking if the user
wants to set up just one node.
```
Do you want to set up more than one cluster member? (yes/no) [default=yes]: 
```

If the user enters `no`, the system will follow the ordinary setup with
ZFS and OVN (or optionally a FAN network instead), but the user will not
be prompted for a lookup subnet and will not be presented a list of
systems.

MicroCeph will be skipped as we require 3 systems. 

The cluster can be grown after this point by using `microcloud add`.

TODO:

- [x] Add tests
- [x] Support preseed
- [x] Support adding missing services (maybe, if it makes sense)
- [x] Test MicroOVN functions properly with 1 node.

cmd/microcloud/add.go

@@ -45,6 +45,7 @@ func (c *cmdAdd) Run(cmd *cobra.Command, args []string) error {
 
 	cfg := initConfig{
 		bootstrap:    false,
+		setupMany:    true,
 		autoSetup:    c.flagAutoSetup,
 		wipeAllDisks: c.flagWipe,
 		common:       c.common,

cmd/microcloud/ask.go

@@ -192,7 +192,7 @@ func (c *initConfig) askAddress() error {
 		return fmt.Errorf("Cloud not find valid subnet for address %q", listenAddr)
 	}
 
-	if !c.autoSetup {
+	if !c.autoSetup && c.setupMany {
 		filter, err := c.asker.AskBool(fmt.Sprintf("Limit search for other MicroCloud servers to %s? (yes/no) [default=yes]: ", subnet.String()), "yes")
 		if err != nil {
 			return err
@@ -1296,6 +1296,10 @@ func (c *initConfig) askCephNetwork(sh *service.Handler) error {
 // In auto setup, we will expect no initialized services so that we can be opinionated about how we configure the cluster without user input.
 // This works by deleting the record for the service from the `service.Handler`, thus ignoring it for the remainder of the setup.
 func (c *initConfig) askClustered(s *service.Handler, expectedServices []types.ServiceType) error {
+	if !c.setupMany {
+		return nil
+	}
+
 	for _, serviceType := range expectedServices {
 		for name, info := range c.state {
 			_, newSystem := c.systems[name]

cmd/microcloud/main_init.go

@@ -81,6 +81,9 @@ type initConfig struct {
 	// autoSetup indicates whether questions should automatically choose defaults.
 	autoSetup bool
 
+	// setupMany indicates whether we are setting up remote nodes concurrently, or just a single cluster member.
+	setupMany bool
+
 	// lookupTimeout is the duration to wait for mDNS records to appear during system lookup.
 	lookupTimeout time.Duration
 
@@ -139,6 +142,7 @@ func (c *cmdInit) Run(cmd *cobra.Command, args []string) error {
 
 	cfg := initConfig{
 		bootstrap:       true,
+		setupMany:       true,
 		address:         c.flagAddress,
 		autoSetup:       c.flagAutoSetup,
 		wipeAllDisks:    c.flagWipeAllDisks,
@@ -176,6 +180,13 @@ func (c *initConfig) RunInteractive(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if !c.autoSetup {
+		c.setupMany, err = c.common.asker.AskBool("Do you want to set up more than one cluster member? (yes/no) [default=yes]: ", "yes")
+		if err != nil {
+			return err
+		}
+	}
+
 	err = c.askAddress()
 	if err != nil {
 		return err
@@ -283,6 +294,10 @@ func (c *initConfig) RunInteractive(cmd *cobra.Command, args []string) error {
 // - `expectedSystems` is a list of expected hostnames. If given, the behaviour is similar to `autoSetup`,
 // except it will wait up to a minute for exclusively these systems to be recorded.
 func (c *initConfig) lookupPeers(s *service.Handler, expectedSystems []string) error {
+	if !c.setupMany {
+		return nil
+	}
+
 	header := []string{"NAME", "IFACE", "ADDR"}
 	var table *SelectableTable
 	var answers []string

cmd/microcloud/main_init_preseed.go

@@ -228,10 +228,6 @@ func (p *Preseed) validate(name string, bootstrap bool) error {
 		return fmt.Errorf("No systems given")
 	}
 
-	if bootstrap && len(p.Systems) < 2 {
-		return fmt.Errorf("At least 2 systems are required to set up MicroCloud")
-	}
-
 	for _, system := range p.Systems {
 		if system.Name == "" {
 			return fmt.Errorf("Missing system name")
@@ -446,9 +442,11 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig) (map[string]InitSyste
 		return nil, fmt.Errorf("Failed to find lookup interface %q", p.LookupInterface)
 	}
 
-	err = c.lookupPeers(s, expectedSystems)
-	if err != nil {
-		return nil, err
+	if len(expectedSystems) > 0 {
+		err = c.lookupPeers(s, expectedSystems)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	expectedServices := make(map[types.ServiceType]service.Service, len(s.Services))
@@ -492,6 +490,11 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig) (map[string]InitSyste
 		}
 	}
 
+	localInfo, err := s.CollectSystemInformation(context.Background(), mdns.ServerInfo{Name: c.name, Address: c.address})
+	if err != nil {
+		return nil, err
+	}
+
 	// If an uplink interface was explicitly chosen, we will try to set up an OVN network.
 	explicitOVN := len(ifaceByPeer) > 0
 
@@ -503,10 +506,12 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig) (map[string]InitSyste
 		}
 
 		// Take the first alphabetical interface for each system's uplink network.
-		for k := range uplinkIfaces {
-			currentIface := ifaceByPeer[system.ServerInfo.Name]
-			if k < currentIface || currentIface == "" {
-				ifaceByPeer[system.ServerInfo.Name] = k
+		if !explicitOVN {
+			for k := range uplinkIfaces {
+				currentIface := ifaceByPeer[system.ServerInfo.Name]
+				if k < currentIface || currentIface == "" {
+					ifaceByPeer[system.ServerInfo.Name] = k
+				}
 			}
 		}
 
@@ -520,30 +525,8 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig) (map[string]InitSyste
 	}
 
 	// If we have specified any part of OVN config, implicitly assume we want to set it up.
-	usingOVN := p.OVN.IPv4Gateway != "" || p.OVN.IPv6Gateway != "" || explicitOVN
-	if usingOVN {
-		// Only select systems not explicitly picked above.
-		infos := make([]mdns.ServerInfo, 0, len(c.systems))
-		for peer, system := range c.systems {
-			if ifaceByPeer[peer] == "" {
-				infos = append(infos, system.ServerInfo)
-			}
-		}
-
-		for _, info := range infos {
-			ifaces, _, _, err := lxd.GetNetworkInterfaces(context.Background(), info.Name, info.Address, info.AuthSecret)
-			if err != nil {
-				return nil, err
-			}
-
-			for k := range ifaces {
-				ifaceByPeer[info.Name] = k
-				break
-			}
-		}
-	}
-
-	// Setup FAN network if OVN not available.
+	hasOVN, _ := localInfo.SupportsOVNNetwork()
+	usingOVN := p.OVN.IPv4Gateway != "" || p.OVN.IPv6Gateway != "" || explicitOVN || hasOVN
 	if usingOVN {
 		for peer, iface := range ifaceByPeer {
 			system := c.systems[peer]
@@ -863,7 +846,8 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig) (map[string]InitSyste
 		return nil, fmt.Errorf("Failed to find at least 1 disk on each machine for local storage pool configuration")
 	}
 
-	if len(cephMatches)+len(directCephMatches) > 0 && p.Storage.CephFS {
+	hasCephFS, _ := localInfo.SupportsRemoteFSPool()
+	if (len(cephMatches)+len(directCephMatches) > 0 && p.Storage.CephFS) || hasCephFS {
 		for name, system := range c.systems {
 			if c.bootstrap {
 				system.TargetStoragePools = append(system.TargetStoragePools, lxd.DefaultPendingCephFSStoragePool())

cmd/microcloud/preseed_test.go

@@ -44,7 +44,7 @@ func (s *preseedSuite) Test_preseedValidateInvalid() {
 			err:    errors.New("No systems given"),
 		},
 		{
-			desc:    "Not enough systems",
+			desc:    "Single node preseed",
 			subnet:  "10.0.0.1/24",
 			iface:   "enp5s0",
 			systems: []System{{Name: "n1", UplinkInterface: "eth0", Storage: InitStorage{}}},
@@ -55,7 +55,7 @@ func (s *preseedSuite) Test_preseedValidateInvalid() {
 			},
 
 			addErr: false,
-			err:    errors.New("At least 2 systems are required to set up MicroCloud"),
+			err:    nil,
 		},
 		{
 			desc:    "Missing lookup subnet",

cmd/microcloud/services.go

@@ -209,6 +209,7 @@ func (c *cmdServiceAdd) Run(cmd *cobra.Command, args []string) error {
 	cfg := initConfig{
 		// Set bootstrap to true because we are setting up a new cluster for new services.
 		bootstrap: true,
+		setupMany: true,
 		common:    c.common,
 		asker:     &c.common.asker,
 		systems:   map[string]InitSystem{},

test/includes/microcloud.sh

@@ -6,14 +6,15 @@ unset_interactive_vars() {
     SETUP_ZFS ZFS_FILTER ZFS_WIPE \
     SETUP_CEPH CEPH_MISSING_DISKS CEPH_FILTER CEPH_WIPE CEPH_ENCRYPT SETUP_CEPHFS CEPH_CLUSTER_NETWORK \
     PROCEED_WITH_NO_OVERLAY_NETWORKING SETUP_OVN OVN_WARNING OVN_FILTER IPV4_SUBNET IPV4_START IPV4_END DNS_ADDRESSES IPV6_SUBNET \
-    REPLACE_PROFILE CEPH_RETRY_HA
+    REPLACE_PROFILE CEPH_RETRY_HA MULTI_NODE
 }
 
 # microcloud_interactive: outputs text that can be passed to `TEST_CONSOLE=1 microcloud init`
 # to simulate terminal input to the interactive CLI.
 # The lines that are output are based on the values passed to the listed environment variables.
 # Any unset variables will be omitted.
 microcloud_interactive() {
+  MULTI_NODE=${MULTI_NODE:-}                     # (yes/no) whether to set up multiple nodes
   SKIP_LOOKUP=${SKIP_LOOKUP:-}                   # whether or not to skip the whole lookup block in the interactive command list.
   LOOKUP_IFACE=${LOOKUP_IFACE:-}                 # filter string for the lookup interface table.
   LIMIT_SUBNET=${LIMIT_SUBNET:-}                 # (yes/no) input for limiting lookup of systems to the above subnet.
@@ -44,11 +45,18 @@ microcloud_interactive() {
   REPLACE_PROFILE="${REPLACE_PROFILE:-}"          # Replace default profile config and devices.
 
   setup=""
-  if ! [ "${SKIP_LOOKUP}" = 1 ]; then
+  if [ -n "${MULTI_NODE}" ]; then
     setup="
+${MULTI_NODE}                                           # lookup multiple nodes
 ${LOOKUP_IFACE}                                         # filter the lookup interface
 $([ -n "${LOOKUP_IFACE}" ] && printf "select")          # select the interface
 $([ -n "${LOOKUP_IFACE}" ] && printf -- "---")
+$(true)
+"
+  fi
+
+  if ! [ "${SKIP_LOOKUP}" = 1 ]; then
+    setup="${setup}
 ${LIMIT_SUBNET}                                             # limit lookup subnet (yes/no)
 $([ "${SKIP_SERVICE}" = "yes" ] && printf "%s" "${SKIP_SERVICE}")  # skip MicroOVN/MicroCeph (yes/no)
 expect ${EXPECT_PEERS}                                      # wait until the systems show up

test/main.sh

@@ -218,6 +218,7 @@ run_instances_tests() {
 
 run_basic_tests() {
   run_test test_reuse_cluster "reuse_cluster"
+  run_test test_add_services "add_services"
   run_test test_auto "auto"
   run_test test_remove_cluster_member "remove_cluster_member"
   run_test test_non_ha "non_ha"

test/suites/add.sh

@@ -119,6 +119,7 @@ test_add_interactive() {
 
   echo "Test growing a MicroCloud with all services and devices set up"
   unset_interactive_vars
+  export MULTI_NODE="yes"
   export LOOKUP_IFACE="enp5s0"
   export LIMIT_SUBNET="yes"
   export EXPECT_PEERS=2
@@ -200,6 +201,7 @@ test_add_interactive() {
   reset_systems 4 2 1
   echo "Test growing a MicroCloud when storage & networks were not already set up"
   unset_interactive_vars
+  export MULTI_NODE="yes"
   export LOOKUP_IFACE="enp5s0"
   export LIMIT_SUBNET="yes"
   export EXPECT_PEERS=2