Chapter 11. Additional network configuration

Procedure

1. Create route_table and interface entries in a custom NIC template from the ~/templates/custom-nics directory, define a route for the interface, and define rules that are relevant to your deployment:

   $network_config:
     network_config:
   
     - type: route_table
       name: custom
       table_id: 200
   
     - type: interface
       name: em1
       use_dhcp: false
       addresses:
         - ip_netmask: 192.0.2.1/24
   
       routes:
         - ip_netmask: 10.1.3.0/24
           next_hop: 192.0.2.5
           route_options: "metric 10"
           table: 200
       rules:
         - rule: "iif em1 table 200"
           comment: "Route incoming traffic to em1 with table 200"
         - rule: "from 192.0.2.0/24 table 200"
           comment: "Route all traffic from 192.0.2.0/24 with table 200"
         - rule: "add blackhole from 172.19.40.0/24 table 200"
         - rule: "add unreachable iif em1 from 192.168.1.0/24"

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2. Set the run-os-net-config.sh script location to an absolute path in each custom NIC template that you create. The script is located in the /usr/share/openstack-tripleo-heat-templates/network/scripts/ directory on the undercloud:

   resources:
     OsNetConfigImpl:
       type: OS::Heat::SoftwareConfig
       properties:
         group: script
         config:
           str_replace:
             template:
               get_file: /usr/share/openstack-tripleo-heat-templates/network/scripts/run-os-net-config.sh

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3. Include your custom NIC configuration and network environment files in the deployment command, along with any other environment files relevant to your deployment:

   $ openstack overcloud deploy --templates \
   -e ~/templates/<custom-nic-template>
   -e <OTHER_ENVIRONMENT_FILES>

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Procedure

1. Check the kernel version.

   ovs-appctl -t ovs-vswitchd dpif/show-dp-features br-int

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2. If the output includes Check pkt length action: No, or if there is no Check pkt length action string in the output, upgrade to RHEL 8.2.0.4 or later, or do not send jumbo frames to an external network that has a smaller MTU.

3. If the output includes Check pkt length action: Yes, set the following value in the [ovn] section of ml2_conf.ini.

   ovn_emit_need_to_frag = True

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Procedure

1. Log in to the undercloud host as the stack user.

2. Source the undercloud credentials file:

   $ source ~/stackrc

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3. Create a custom YAML environment file.

   Example

   $ vi /home/stack/templates/my-environment.yaml

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4. Your environment file must contain the keywords parameter_defaults and ExtraSysctlSettings. Enter a new value for the maximum number of connections that netfilter can track in the variable, net.nf_conntrack_max.

   Example

   In this example, you can set the conntrack limit across all hosts in your RHOSP deployment:

   parameter_defaults:
     ExtraSysctlSettings:
       net.nf_conntrack_max:
         value: 500000

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   Use the <role>Parameter parameter to set the conntrack limit for a specific role:

   parameter_defaults:
     <role>Parameters:
       ExtraSysctlSettings:
         net.nf_conntrack_max:
           value: <simultaneous_connections>

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   • Replace <role> with the name of the role.

     For example, use ControllerParameters to set the conntrack limit for the Controller role, or ComputeParameters to set the conntrack limit for the Compute role.

   • Replace <simultaneous_connections> with the quantity of simultaneous connections that you want to allow.

     Example

     In this example, you can set the conntrack limit for only the Controller role in your RHOSP deployment:

     parameter_defaults:
       ControllerParameters:
         ExtraSysctlSettings:
           net.nf_conntrack_max:
             value: 500000

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     Note

     The default value for net.nf_conntrack_max is 500000 connections. The maximum value is: 4294967295.

5. Run the deployment command and include the core heat templates, environment files, and this new custom environment file.

   Important

   The order of the environment files is important as the parameters and resources defined in subsequent environment files take precedence.

   Example

   $ openstack overcloud deploy --templates \
   -e /home/stack/templates/my-environment.yaml

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