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Merge pull request #31142 from jboxman/OSDOCS-1860
OSDOCS#1860 - OpenShift SDN egress IPs are balanced equally
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‎modules/nw-egress-ips-about.adoc‎

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@@ -193,22 +193,27 @@ When using the automatic assignment approach for egress IP addresses the followi
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- You set the `egressCIDRs` parameter of each node's `HostSubnet` resource to indicate the range of egress IP addresses that can be hosted by a node.
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{product-title} sets the `egressIPs` parameter of the `HostSubnet` resource based on the IP address range you specify.
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ifeval::[{product-version} < 4.8]
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- Only a single egress IP address per namespace is supported when using the automatic assignment mode.
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endif::[]
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If the node hosting the namespace's egress IP address is unreachable, {product-title} will reassign the egress IP address to another node with a compatible egress IP address range.
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The automatic assignment approach works best for clusters installed in environments with flexibility in associating additional IP addresses with nodes.
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[id="considerations-manual-egress-ips"]
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== Considerations when using manually assigned egress IP addresses
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This approach is recommended for clusters installed in public cloud environments, where there can be limitations on associating additional IP addresses with nodes.
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When using the manual assignment approach for egress IP addresses the following considerations apply:
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- You set the `egressIPs` parameter of each node's `HostSubnet` resource to indicate the IP addresses that can be hosted by a node.
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- Multiple egress IP addresses per namespace are supported.
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When a namespace has multiple egress IP addresses, if the node hosting the first egress IP address is unreachable, {product-title} will automatically switch to using the next available egress IP address until the first egress IP address is reachable again.
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If a namespace has multiple egress IP addresses and those addresses are hosted on multiple nodes, the following additional considerations apply:
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This approach is recommended for clusters installed in public cloud environments, where there can be limitations on associating additional IP addresses with nodes.
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- If a pod is on a node that is hosting an egress IP address, that pod always uses the egress IP address on the node.
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- If a pod is not on a node that is hosting an egress IP address, that pod uses an egress IP address at random.
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endif::openshift-sdn[]
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ifdef::openshift-sdn[]

‎modules/nw-egress-ips-automatic.adoc‎

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@@ -1,6 +1,6 @@
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// Module included in the following assemblies:
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//
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// * networking/assigning-egress-ips.adoc
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// * networking/openshift_sdn/assigning-egress-ips.adoc
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[id="nw-egress-ips-automatic_{context}"]
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= Configuring automatically assigned egress IP addresses for a namespace
@@ -20,16 +20,20 @@ following JSON:
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+
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[source,terminal]
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----
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$ oc patch netnamespace <project_name> --type=merge -p \ <1>
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$ oc patch netnamespace <project_name> --type=merge -p \
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'{
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"egressIPs": [
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"<ip_address>" <2>
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"<ip_address>"
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]
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}'
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----
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<1> Specify the name of the project.
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<2> Specify a single egress IP address. Using multiple IP addresses is not
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supported.
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+
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--
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where:
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`<project_name>`:: Specifies the name of the project.
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`<ip_address>`:: Specifies one or more egress IP addresses for the `egressIPs` array.
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--
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+
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For example, to assign `project1` to an IP address of 192.168.1.100 and
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`project2` to an IP address of 192.168.1.101:
@@ -47,15 +51,20 @@ parameter for each host using the following JSON:
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+
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[source,terminal]
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----
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$ oc patch hostsubnet <node_name> --type=merge -p \ <1>
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$ oc patch hostsubnet <node_name> --type=merge -p \
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'{
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"egressCIDRs": [
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"<ip_address_range_1>", "<ip_address_range_2>" <2>
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"<ip_address_range>", "<ip_address_range>"
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]
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}'
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----
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<1> Specify a node name.
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<2> Specify one or more IP address ranges in CIDR format.
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+
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--
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where:
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`<node_name>`:: Specifies a node name.
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`<ip_address_range>`:: Specifies an IP address range in CIDR format. You can specify more than one address range for the `egressCIDRs` array.
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--
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For example, to set `node1` and `node2` to host egress IP addresses
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in the range 192.168.1.0 to 192.168.1.255:

‎modules/nw-egress-ips-static.adoc‎

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// Module included in the following assemblies:
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//
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// * networking/assigning-egress-ips.adoc
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// * networking/openshift_sdn/assigning-egress-ips.adoc
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[id="nw-egress-ips-static_{context}"]
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= Configuring manually assigned egress IP addresses for a namespace
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+
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[source,terminal]
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----
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$ oc patch netnamespace <project> --type=merge -p \ <1>
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$ oc patch netnamespace <project_name> --type=merge -p \
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'{
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"egressIPs": [ <2>
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"egressIPs": [
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"<ip_address>"
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]
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]
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}'
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----
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<1> Specify the name of the project.
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<2> Specify one or more egress IP addresses. The `egressIPs` parameter is an
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array.
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+
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For example, to assign the `project1` project to an IP address of
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`192.168.1.100`:
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--
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where:
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`<project_name>`:: Specifies the name of the project.
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`<ip_address>`:: Specifies one or more egress IP addresses for the `egressIPs` array.
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--
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+
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For example, to assign the `project1` project to the IP addresses `192.168.1.100` and `192.168.1.101`:
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[source,terminal]
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----
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$ oc patch netnamespace project1 --type=merge \
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-p '{"egressIPs": ["192.168.1.100"]}'
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-p '{"egressIPs": ["192.168.1.100","192.168.1.101"]}'
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----
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You can set `egressIPs` to two or more IP addresses on different nodes to
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provide high availability. If multiple egress IP addresses are set, pods use the
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first IP in the list for egress, but if the node hosting that IP address fails,
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pods switch to using the next IP in the list after a short delay.
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To provide high availability, set the `egressIPs` value to two or more IP addresses on different nodes. If multiple egress IP addresses are set, then pods use all egress IP addresses roughly equally.
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. Manually assign the egress IP to the node hosts. Set the `egressIPs` parameter
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on the `HostSubnet` object on the node host. Using the following JSON, include
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as many IPs as you want to assign to that node host:
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as many IP addresses as you want to assign to that node host:
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[source,terminal]
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----
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$ oc patch hostsubnet <node_name> --type=merge -p \ <1>
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$ oc patch hostsubnet <node_name> --type=merge -p \
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'{
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"egressIPs": [ <2>
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"<ip_address_1>",
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"<ip_address_N>"
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"egressIPs": [
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"<ip_address>",
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"<ip_address>"
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]
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}'
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----
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<1> Specify the name of the node.
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<2> Specify one or more egress IP addresses. The `egressIPs` field is an array.
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+
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--
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where:
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`<node_name>`:: Specifies a node name.
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`<ip_address>`:: Specifies an IP address. You can specify more than one IP address for the `egressIPs` array.
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--
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For example, to specify that `node1` should have the egress IPs `192.168.1.100`,
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`192.168.1.101`, and `192.168.1.102`:
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'{"egressIPs": ["192.168.1.100", "192.168.1.101", "192.168.1.102"]}'
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----
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In the previous example, all egress traffic for `project1` will be routed to the
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node hosting the specified egress IP, and then connected (using NAT) to that IP
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address.
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In the previous example, all egress traffic for `project1` will be routed to the node hosting the specified egress IP, and then connected through Network Address Translation (NAT) to that IP address.

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