Istio proxy uid 1337

使用 istioctl kube-inject 生成的 init-container ，会有如下格式的参数：

      initContainers:
      - args:
        - -p
        - "15001"
        - -u
        - "1337"
        - -m
        - REDIRECT
        - -i
        - '*'
        - -x
        - ""
        - -b
        - "9080"
        - -d
        - ""

其中 uid 1337 很诡异，根据 istio 的 ./tools/deb/istio-iptables.sh -h 命令文档说明：

-u: Specify the UID of the user for which the redirection is not
      applied. Typically, this is the UID of the proxy container
      (default to uid of $ENVOY_USER, uid of istio_proxy, or 1337)

以及代码 istio-proxy uid hardcoded 可以定位到 1337 是 istio 写死在代码里面的，后续 istio 加上了说明：https://github.com/istio/istio.io/pull/2940/files

_**Application UIDs**_: Do **not** run applications as a user with the user ID (UID) value of **1337**.