golang 报错 `tls: failed to verify certificate: x509: certificate signed by unknown authority`

golang服务使用 Docker 打包镜像，部署到 k8s 后出现如下的错误信息：

tls: failed to verify certificate: x509: certificate signed by unknown authority

报错的位置是 golang 的 http client，并未有很特殊的配置。

刚开始以为是域名证书的问题，最后发现是因为使用了 debian 的镜像：

FROM debian:bullseye

决办法是加上证书更新的语句：

FROM debian:bullseye

# 基础镜像的证书未更新，导致 https 的请求出现类似错误
# tls: failed to verify certificate: x509: certificate signed by unknown authority
RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*

用最小镜像也能解决这个问题：

FROM alpine:3.20.0