Bug 1582685

Description of problem:

The `ocf:heartbeat:IPsrcaddr` resource agent updates the default route to use a specified IP address (`OCF_RESKEY_ipaddress`) as the preferred source IP. It does not make any changes to the local route table.

`IPsrcaddr` is often paired with `IPaddr2` to provide a virtual IP address and then use that virtual IP as the preferred source IP for outgoing connections on the default route. Some applications make local connections to the virtual IP address, and a subset of those require that the source IP for the connection be the virtual IP.

In other words, the local connection in these cases needs to be:
    virtual_ip -> virtual_ip

However, this is what is occurring:
    primary_ip -> virtual_ip


The local routing table determines the source IP for these connections. For routes in the local routing table, the default src IP address has always been the primary IP address of the interface. After adding an `IPaddr2` resource, there will be a local route like this:

    # ip route show table local to exact <virtual_ip>
    local <virtual_ip> dev <iface> proto kernel scope host src <primary_ip>


On RHEL 6, due to a bug, the kernel ignored the src specification when handling local routing. Instead, it used the destination IP as the source IP. So applications that depended on "virtual_ip -> virtual_ip" behavior behaved normally. For more information, see "Source IP address selection is different in RHEL7 compared to RHEL6 for local connections" (https://access.redhat.com/solutions/3458491).

On RHEL 7, the kernel respects the src specification for local routes. So applications that depend on "virtual_ip -> virtual_ip" behavior will break.

The IPsrcaddr resource agent needs to be able to update the local route to `OCF_RESKEY_ipaddress` in addition to updating the default route.


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Version-Release number of selected component (if applicable):

resource-agents-3.9.5-124.el7.x86_64
master


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How reproducible:

Always


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Steps to Reproduce:

1. Create a resource group containing both an IPaddr2 resource and an IPsrcaddr resource with the same IP address ($IPADDR).

    # pcs resource show ip
     Group: ip
      Resource: vip (class=ocf provider=heartbeat type=IPaddr2)
       Attributes: ip=192.168.122.61
       Operations: monitor interval=60s timeout=20s (vip-monitor-interval-60s)
                   stop interval=0s timeout=20s (vip-stop-interval-0s)
                   start interval=0s timeout=20s (vip-start-interval-0s)
      Resource: ipsrc (class=ocf provider=heartbeat type=IPsrcaddr)
       Attributes: ipaddress=192.168.122.61
       Operations: monitor interval=10 timeout=20s (ipsrc-monitor-interval-10)
                   start interval=0s timeout=20s (ipsrc-start-interval-0s)
                   stop interval=0s timeout=20s (ipsrc-stop-interval-0s)


2. Verify that the default route has been updated to use "$IPADDR" as the source IP.

    # ip route show to exact 0.0.0.0/0
    default via 192.168.122.1 dev eth0 proto static src 192.168.122.61 metric 100 


3. Observe that the local route to "$IPADDR" still uses the primary IP address as the source IP.

    # ip route show table local to exact 192.168.122.61
    local 192.168.122.61 dev eth0 proto kernel scope host src 192.168.122.51 


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Actual results:

    # ip route show table local to exact 192.168.122.61
    local 192.168.122.61 dev eth0 proto kernel scope host src 192.168.122.51 


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Expected results:

    # ip route show table local to exact 192.168.122.61
    local 192.168.122.61 dev eth0 proto kernel scope host src 192.168.122.61 


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Additional info:

N/A