问题情况
Docker版本在v23.0以后，只要Dockerfile中FROM的私库镜像不存在本地，就会报错：
# 我本地是v24.0.2版本Docker
[root@localhost ipd]# docker build . -t harbor.xxx.com.cn/test/bap:2.7.1
[+] Building 0.6s (3/3) FINISHED docker:default
=> [internal] load build definition from Dockerfile 0.2s
=> => transferring dockerfile: 1.05kB 0.0s
=> [internal] load .dockerignore 0.2s
=> => transferring context: 2B 0.0s
=> ERROR [internal] load metadata for harbor.xxx.com.cn/xxx/tomcat:8.5.90-jdk8-temurin 0.0s
------
> [internal] load metadata for harbor.xxx.com.cn/xxx/tomcat:8.5.90-jdk8-temurin:
------
Dockerfile:2
--------------------
1 | #指定基础镜像
2 | >>> FROM harbor.xxx.com.cn/xxx/tomcat:8.5.90-jdk8-temurin
3 | #指定环境变量，时区
4 | ENV TZ=Asia/Shanghai
--------------------
ERROR: failed to solve: harbor.xxx.com.cn/xxx/tomcat:8.5.90-jdk8-temurin: failed to do request: Head "https://harbor.xxx.com.cn/v2/xxx/tomcat/manifests/8.5.90-jdk8-temurin": tls: failed to verify certificate: x509: certificate signed by unknown authority
但我已经在 /etc/docker/daemon.json 中正确配置了 insecure-registries了，即能 pull 也能 push。
问题原因
Docker在v23.0版本及以后，使用了build-kit代替了旧的实现，目前build-kit对insecure-registries配置可能没做兼容，构建Dockerfile FROM镜像时未判断是私库，导致报错。
处理方式
目前(2023.07.21)办法就一个，在 ~/.bashrc 或 /etc/profile 添加一行 export DOCKER_BUILDKIT=0，然后 source 一个修改的配置文件。
命令示例：
echo "export DOCKER_BUILDKIT=0" >> ~/.bashrc
source ~/.bashrc
后边如果有新的处理办法或者哪个版本解决这个问题，再来更贴。
本文引用：
- https://github.com/docker/cli/blob/master/docs/deprecated.md#legacy-builder-fallback
- https://github.com/docker/buildx/issues/1642
- https://github.com/docker/buildx/issues/1687
- https://github.com/docker/docs/pull/17746
- https://github.com/moby/buildkit/pull/3382