Lab3.2 worker node failed to join master

Sorry for last post. After further testing, I found it's not working. Here is more details:
Environment (AWS VPC ec2 x 2 medium) OS: ubuntu 16.04 LTS

[preflight] running pre-flight checks
    [WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs ip_vs_rr ip_vs_wrr ip_vs_sh] or no builtin kernel ipvs support: map[nf_conntrack_ipv4:{} ip_vs:{} ip_vs_rr:{} ip_vs_wrr:{} ip_vs_sh:{}]
you can solve this problem with following methods:
 1. Run 'modprobe -- ' to load missing kernel modules;
2. Provide the missing builtin kernel ipvs support

[discovery] Trying to connect to API Server "172.31.57.36:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://172.31.57.36:6443"
[discovery] Requesting info from "https://172.31.57.36:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "172.31.57.36:6443"
[discovery] Successfully established connection with API Server "172.31.57.36:6443"
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.12" ConfigMap in the kube-system namespace
configmaps "kubelet-config-1.12" is forbidden: User "system:bootstrap:tlx9nt" cannot get resource "configmaps" in API group "" in the namespace "kube-system"

Try on master

kubectl get node
NAME              STATUS   ROLES    AGE   VERSION
ip-172-31-57-36   Ready    master   57m   v1.12.1

Master shows join failed.