今天安装k8sV1.16的版本时候，执行突然发现命令不对，之前安装V1.15的时候是可以的，可能是版本升级的原因。
解决：
unknown flag: --experimental-upload-certs，将–experimental-upload-certs 替换为 --upload-certs
[root@k8s-master opt]# kubeadm init --config=kubeadm-config.yaml --experimental-upload-certs | tee kubeadm-init.log
Error: unknown flag: --experimental-upload-certs
Usage:
kubeadm init [flags]
kubeadm init [command] Available Commands:
phase Use this command to invoke single phase of the init workflow Flags:
--apiserver-advertise-address string The IP address the API Server will advertise it's listening on. If not set the default network interface will be used.
--apiserver-bind-port int32 Port for the API Server to bind to. (default 6443)
--apiserver-cert-extra-sans strings Optional extra Subject Alternative Names (SANs) to use for the API Server serving certificate. Can be both IP addresses and DNS names.
--cert-dir string The path where to save and store the certificates. (default "/etc/kubernetes/pki")
--certificate-key string Key used to encrypt the control-plane certificates in the kubeadm-certs Secret.
--config string Path to a kubeadm configuration file.
--control-plane-endpoint string Specify a stable IP address or DNS name for the control plane.
--cri-socket string Path to the CRI socket to connect. If empty kubeadm will try to auto-detect this value; use this option only if you have more than one CRI installed or if you have non-standard CRI socket.
--dry-run Don't apply any changes; just output what would be done.
-k, --experimental-kustomize string The path where kustomize patches for static pod manifests are stored.
--feature-gates string A set of key=value pairs that describe feature gates for various features. Options are:
IPv6DualStack=true|false (ALPHA - default=false)
-h, --help help for init
--ignore-preflight-errors strings A list of checks whose errors will be shown as warnings. Example: 'IsPrivilegedUser,Swap'. Value 'all' ignores errors from all checks.
--image-repository string Choose a container registry to pull control plane images from (default "k8s.gcr.io")
--kubernetes-version string Choose a specific Kubernetes version for the control plane. (default "stable-1")
--node-name string Specify the node name.
--pod-network-cidr string Specify range of IP addresses for the pod network. If set, the control plane will automatically allocate CIDRs for every node.
--service-cidr string Use alternative range of IP address for service VIPs. (default "10.96.0.0/12")
--service-dns-domain string Use alternative domain for services, e.g. "myorg.internal". (default "cluster.local")
--skip-certificate-key-print Don't print the key used to encrypt the control-plane certificates.
--skip-phases strings List of phases to be skipped
--skip-token-print Skip printing of the default bootstrap token generated by 'kubeadm init'.
--token string The token to use for establishing bidirectional trust between nodes and control-plane nodes. The format is [a-z0-9]{6}\.[a-z0-9]{16} - e.g. abcdef.0123456789abcdef
--token-ttl duration The duration before the token is automatically deleted (e.g. 1s, 2m, 3h). If set to '0', the token will never expire (default 24h0m0s)
--upload-certs Upload control-plane certificates to the kubeadm-certs Secret. Global Flags:
--add-dir-header If true, adds the file directory to the header
--log-file string If non-empty, use this log file
--log-file-max-size uint Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)
--rootfs string [EXPERIMENTAL] The path to the 'real' host root filesystem.
--skip-headers If true, avoid header prefixes in the log messages
--skip-log-headers If true, avoid headers when opening log files
-v, --v Level number for the log level verbosity Use "kubeadm init [command] --help" for more information about a command. unknown flag: --experimental-upload-certs
To see the stack trace of this error execute with --v=5 or higher
[root@k8s-master opt]# kubeadm init --config=kubeadm-config.yaml --upload-certs | tee kubeadm-init.log
[init] Using Kubernetes version: v1.16.1
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.180.121]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.180.121 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.180.121 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file