Unable to add IPs to VPS on SolusVM 2: failed to update network for virtual server

Symptoms

Error is seen in the UI:

SVM_ERROR: failed to update network for virtual server "<UUID>" with parameters (kvm.ChangeIPsParameters) { OperatingSystemType: (internal.OperatingSystemType) (len=5) "Linux", ISOImageUUID: (string) (len=36) "<UUID>", ISOStoragePath: (string) (len=31) "/usr/local/solus/iso_images/108", IPs: ([]string) (len=1 cap=1) { (string) (len=12) "192.168.1.100" }, Network: (network.VirtualServerNetwork) { Bridge: (network.Bridge) { Type: (network.BridgeType) (len=6) "routed", Name: (string) (len=9) "br-routed" }, Interface: (network.InterfaceName) (len=7) "sol-108", MacAddress: (string) (len=17) "52:54:00:c0:93:dd", IsolationRules: ([]network.RuleName) (len=4 cap=4) { (network.RuleName) (len=3) "arp", (network.RuleName) (len=4) "dhcp", (network.RuleName) (len=10) "cloud_init", (network.RuleName) (len=10) "portmapper" }, Blocks: ([]network.Block) (len=2 cap=2) { (network.Block) { Type: (network.IPVersion) (len=4) "IPv4", Ip: (string) (len=12) "192.168.1.100", Gateway: (string) (len=12) "192.168.1.1", NameServers: ([]string) (len=2 cap=2) { (string) (len=7) "8.8.8.8", (string) (len=7) "8.8.4.4" }, NetMask: (string) (len=15) "255.255.255.224", Subnet: (string) "", Cidr: (string) (len=2) "27" }, (network.Block) { Type: (network.IPVersion) (len=4) "IPv4", Ip: (string) (len=12) "192.168.1.100", Gateway: (string) (len=12) "192.168.1.1", NameServers: ([]string) (len=2 cap=2) { (string) (len=7) "8.8.8.8", (string) (len=7) "8.8.4.4" }, NetMask: (string) (len=15) "255.255.255.224", Subnet: (string) "", Cidr: (string) (len=2) "27" } }, Vlan: (network.VlanConfig) { IsEnabled: (bool) false, Tag: (int) 0, Mode: (network.VlanMode) "", Trunks: ([]int) <nil> } } } : update running virtual server: failed to run vmagent on the virtual server: failed to exec "guest-exec" command with arguments (agent.execArguments) { Path: (string) (len=42) "/var/lib/cloud/scripts/per-boot/vmagent.sh", Arg: ([]string) <nil>, Env: ([]string) <nil>, InputData: ([]uint8) <nil>, CaptureOutput: (bool) true } : failed to exec virsh qemu-agent-command, got output "error: internal error: unable to execute QEMU agent command 'guest-exec': Guest agent command failed, error was 'Failed to execute child process “/var/lib/cloud/scripts/per-boot/vmagent.sh” (Permission denied)'\n\n": exit status 1

Cause

When trying to change a VPS IP while the VPS itself is still working.

Resolution

1. Stop the VM from SolusVM2
2. Add the IP again
3. Start the VPS

Note: Here is the guide on adding a new IP: How-to-assign-an-additional-IP-address-to-SolusVM-2-VPS