Only run stack.sh once, even if you want to have compute services on the controller.

And as I said, use the original repo, not trystack.cn. I encountered somebody with other problems, and removing trystack.cn was the solution: https://ask.openstack.org/en/questio...260-setglance/

I can't understand these two sentences：
FIXED_RANGE=10.4.128.0/20
FLOATING_RANGE=192.168.42.128/25

Devstack, by default, creates an external network it names public, and a tenant network named private.

FIXED_RANGE is the IP address range for private, FLOATING_RANGE is the range for public. See also here: https://docs.openstack.org/devstack/...e-machine.html.

Thank you.I make it .
1)
If I want to reinstall the control node (A), whether the compute nodes (B, C) previously installed on the control node (A) still need to be reinstalled,
if i don't need to re-install the compute nodes(B、C)，If i still need to run /opt/stack/devstack/tools/ Discover_hosts.sh in node A.
2)
I have edited the local.conf in control node A(192.168.99.206) :
FIXED_RANGE=10.0.1.0/24,but i don't see anything change in network when i check the control node's dashboard.

I am sorry to bother you again.
Because I found that my OpenStack assigned an IP address to my instance, but when i opened the console and found that the IP of this virtual machine was not assigned.

Normally, instances get their IP addresses via DHCP. You either attached the instance to a network that doesn't enable DHCP, or something is wrong with your network or Neutron configuration.

1)Ubuntu server version is :18.04
2)50-cloud-init.yaml is this :
network:
ethernets:
eth0:
addresses: [192.168.99.206/16]
gateway4: 192.168.99.2
nameservers:
addresses: [202.112.144.236,202.112.144.246]
eth1:
addresses: [77.77.77.206/24]
version: 2
3)controller's local.conf is this :
[[local|localrc]]

#PUBLIC network
PUBLIC_INTERFACE=eth1
HOST_IP=192.168.99.206
PUBLIC_NETWORK_GATEWAY=192.168.99.2

FLOATING_RANGE=192.168.99.206/16
#Q_FLOATING_ALLOCATION_POOL=start=192.168.99.210,end=192.168.99.254

#PRIVATE network

#FIXED_RANGE=10.0.1.0/24

#system log
LOGFILE=/opt/stack/logs/stack.sh.log
SYSLOG_HOST=192.168.99.206

#set password
ADMIN_PASSWORD=bjtungirc
DATABASE_PASSWORD=bjtungirc
RABBIT_PASSWORD=bjtungirc
SERVICE_PASSWORD=bjtungirc

#enable service
enable_service s-proxy s-object s-container s-account


Thanks.

To which network is the instance attached? Does this network have DHCP?

By the way, I am not sure, but I think that PUBLIC_NETWORK_GATEWAY should refer to the gateway for eth1. However this is unlikely to be related to your current problem.

1)
I follow the page https://docs.openstack.org/devstack/...etworking.html
It says that
If you have 2 or more interfaces on your devstack server, you can allocate an interface to neutron to fully manage. This should not be the same interface you use to ssh into the devstack server itself.
This is done by setting with the PUBLIC_INTERFACE attribute.

2)
The instance attaches the network 192.168.0.0/16,public-subnet 192.168.0.0/16,i want it to access the external network.
this network（192.168.0.0/16） doesn't have DHCP.
3)
i don't set the gateway for eth1.
If i set it ,should i set IP address for eth1 in 192.168.x.x/16 or 77.77.77.x/24

Well, that explains why the instance doesn't get an IP address.
I'd say that depends on your settings outside of the cloud. Personally I have no experience with Devstack on a multihomed host.

thanks，if i want to use linux-bridge.How should I set it up?

I have never tried Linuxbridge with Devstack. You need to check the documentation.

If i use the OVS bridge to make the VM access the external network.The network must be DHCP.

External access and DHCP are two different things. DHCP is one method for getting an IP address (and by far the most commmon in a cloud), but for instances connected to the external network, you could use your own DHCP server outside of the cloud instead of Neutron's DHCP service. You can also set a static IP address in the VM (I don't know how common that is).

Why did you attach the instance to the external network? Normally, you attach them to a tenant network where DHCP is enabled. By default, Devstack sets up a tenant network named private, which is routed to the external network. This is where I would attach instances.

You say:
Devstack sets up a tenant network named private, which is routed to the external network.

How to let the private network be routed to the external network.