Perf & scale team is running scale tests to to find out maximum supported egress ips and come across this issue. When we have 55339 egress ip objects (each egress ip object with one egress ip address) in 118 worker node baremetal cluster, multus-admission-controller pod is stuck in CrashLoopBackOff state.

"oc describe pod" command output is copied here http://storage.scalelab.redhat.com/anilvenkata/multus-admission/multus-admission-controller-84b896c8-kmvdk.describe 

"oc describe pod" shows that the names of all 55339 egress ips are passed to container's exec command 
#cat multus-admission-controller-84b896c8-kmvdk.describe  | grep ignore-namespaces | tr ',' '\n' | grep -c egressip
55339

and exec command is failing as this argument list is too long.
# oc logs  -n openshift-multus multus-admission-controller-84b896c8-kmvdk
Defaulted container "multus-admission-controller" out of: multus-admission-controller, kube-rbac-proxy
exec /bin/bash: argument list too long

# oc get co network
NAME      VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
network   4.14.16   True        True          False      35d     Deployment "/openshift-multus/multus-admission-controller" update is rolling out (1 out of 3 updated)

# oc describe pod -n openshift-multus multus-admission-controller-84b896c8-kmvdk > multus-admission-controller-84b896c8-kmvdk.describe
 
# oc get pods -n openshift-multus  | grep multus-admission-controller
multus-admission-controller-6c58c66ff9-5x9hn   2/2     Running            0                35d
multus-admission-controller-6c58c66ff9-zv9pd   2/2     Running            0                35d
multus-admission-controller-84b896c8-kmvdk     1/2     CrashLoopBackOff   26 (2m56s ago)   110m

As this environment has 55338 namespaces (each namespace with 1 pod and 1 eip object), it will hard to capture must gather.  

    4.14.16

    always

    1. use kube-burner to create 55339 egress ip obejct, each object with one egress ip address. 
    2. We will see multus-admission-controller pod stuck in CrashLoopBackOff