我使用 Calico 网络层在 Kubernetes 主机上遇到了与网络相关的问题。对于持续集成，我需要在 docker 中运行 docker，但是docker build使用这个Dockerfile运行起来很简单：
FROM praqma/network-multitool AS build
RUN route
RUN ping -c 4 google.com
RUN traceroute google.com
产生输出：
Step 1/4 : FROM praqma/network-multitool AS build
---> 3619cb81e582
Step 2/4 : RUN route
---> Running in 80bda13a9860
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 172.17.0.1 0.0.0.0 UG 0 0 0 eth0
172.17.0.0 * 255.255.0.0 U 0 0 0 eth0
Removing intermediate container 80bda13a9860
---> d79e864eafaf
Step 3/4 : RUN ping -c 4 google.com
---> Running in 76354a92a413
PING google.com (216.58.201.110) 56(84) bytes of data.
--- google.com ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 53ms
---> 3619cb81e582
Step 4/4 : RUN traceroute google.com
---> Running in 3aa7908347ba
traceroute to google.com (216.58.201.110), 30 hops max, 46 byte packets
1 172.17.0.1 (172.17.0.1) 0.009 ms 0.005 ms 0.003 ms
似乎 docker 容器在 Kubernetes 上创建时路由无效。Kubernetes 编排的 Pod 可以正常访问 Internet。
bash-5.0# ping -c 3 google.com
PING google.com (216.58.201.110) 56(84) bytes of data.
64 bytes from prg03s02-in-f14.1e100.net (216.58.201.110): icmp_seq=1 ttl=55 time=0.726 ms
64 bytes from prg03s02-in-f14.1e100.net (216.58.201.110): icmp_seq=2 ttl=55 time=0.586 ms
64 bytes from prg03s02-in-f14.1e100.net (216.58.201.110): icmp_seq=3 ttl=55 time=0.451 ms
--- google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 10ms
rtt min/avg/max/mdev = 0.451/0.587/0.726/0.115 ms
bash-5.0# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 169.254.1.1 0.0.0.0 UG 0 0 0 eth0
169.254.1.1 * 255.255.255.255 UH 0 0 0 eth0
bash-5.0# traceroute google.com
traceroute to google.com (216.58.201.110), 30 hops max, 46 byte packets
1 10-68-149-194.kubelet.kube-system.svc.kube.example.com (10.68.149.194) 0.006 ms 0.005 ms 0.004 ms