Ice Breaking Topics

• How often do you exercise?
• Is a life that focuses on avoiding pain and seeking out pleasure a good and worthwhile life? Why or why not?
• How do you stay informed about current events and global issues?
• If you could only communicate with one type of animal for the rest of your life, what would it be and why?
• Have you ever snuck out of the house?
• How do you want to feel at the end of your life?
• What is the most important quality you look for in a friend or partner?
• What do you do in your spare time?

Most common short names for Kubernetes resources which was used in command kubectl get:

po or pod: Pods
deploy or deployment: Deployments
svc or service: Services
cm or configmap: ConfigMaps
secret: Secrets
pv or persistentvolume: Persistent Volumes
pvc or persistentvolumeclaim: Persistent Volume Claims
sts or statefulset: StatefulSets
job: Jobs
cronjob: CronJobs

git pull 时提示Authentication failed ，需要重置密码，执行这个即可

git config --system --unset credential.helper

首先说明下，本文是以树莓派作为客户端连接ss， 再用privoxy自动代理实现科学研究。
1 安装ss apt-get install shadowsocks-libev

2 禁用这个服务端服务 systemctl disable shadowsocks-libev

3 自动开启这个客户端连接服务 systemctl enable shadowsocks-libev-local@config

4 编辑ss的配置文件 vi /etc/shadowsocks-libev/config.json

事情源于在树莓派上写的定时脚本，定时获取停车费用信息。ubuntu重装后时区都用tzselect设置了，但仍在半夜收到消息通知。
于是发现需要这样设置下。

执行这个设置成中国时区 timedatectl set-timezone Asia/Shanghai

查看本地时间 timedatectl status

还有最重要的，要重启下crontab的服务. systemctl restart cron
有些系统中crontab服务为 crond。

更多关于timedatectl的帮助可以查看这个：

问题来源于raspberry pi4 安装了打印服务，但是cups服务有点异常报，/etc/securetty找不到。
查了下应该是ubuntu 20.04的bug.

root@ubuntu:~# systemctl status cups
● cups.service - CUPS Scheduler
     Loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2020-07-01 00:58:26 CST; 12min ago
TriggeredBy: ● cups.path
             ● cups.socket
       Docs: man:cupsd(8)
   Main PID: 8324 (cupsd)
      Tasks: 2 (limit: 4434)
     CGroup: /system.slice/cups.service
             ├─8324 /usr/sbin/cupsd -l
             └─9318 /usr/lib/cups/notifier/dbus dbus://

Jul 01 01:08:15 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:15 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:22 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:22 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:27 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:27 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:29 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:29 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:39 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory
Jul 01 01:08:39 ubuntu cupsd[8324]: pam_unix(cups:auth): Couldn't open /etc/securetty: No such file or directory

解决的办法就是新建这个文件/etc/securetty，内容为

镜像地址 https://mirrors.huaweicloud.com/centos-altarch/7.7.1908/isos/armhfp/CentOS-Userland-7-armv7hl-RaspberryPI-Minimal-4-1908-sda.raw.xz

CentOS8貌似还没有树莓派的编译版本。

准备另一个32G的tf卡， 用SDCardFormater格式化，再用dd命令烧写。
diskutil umount /dev/disk3s1 别忘了这句

sudo dd bs=64m if=~/Downloads/CentOS-Userland-7-armv7hl-RaspberryPI-Minimal-4-1908-sda.raw of=/dev/disk3

连接网线开机。

在mac上用nmap扫出IP. nmap可以用brew 装
nmap -sn 192.168.1.0/24

第一种方法：定义环境变量

//无需用户名和密码
export http_proxy=http://ip:port
export https_proxy=http://ip:port

//需要用户名和密码
export http_proxy=http://user:password@ip:port
export https_proxy=https://user:password@ip:port

第二种方法：在执行curl时加参数-x

curl -x <[protocol://][user:password@]proxyhost[:port]> url
--proxy <[protocol://][user:password@]proxyhost[:port]> url
--proxy http://user:password@Your-Ip-Here:Port url
-x http://user:password@Your-Ip-Here:Port url

如
curl -x http://mike:123456@api.baidu.com:3392 https://www.zixi.org

*args 和 **kwargs 均为可变参数，方便记忆可以理解为 *args是列表形式的多个参数，不过它传值不是以list, 就是func(arg1, arg2, arg3...)
**kwargs可以理解为字典形式的多组key, value键值对，不过它传值也不是字典，而是func(a=1, b=2, c=3...)。

它们同时出现在func的定义中时，*args在前， **kwargs在后

**kwargs通常用在类的初始化多个配置项参数值传递。举一个pymongo的例子：

class MongoClient(common.BaseObject):
    def __init__(
            self,
            host=None,
            port=None,
            document_class=dict,
            tz_aware=None,
            connect=None,
            type_registry=None,
            **kwargs):

第一种方法：

rds = redis.StrictRedis(host='localhost', port=6379, password='123456')

第二种方法：

redis_config = {
        'host': os.getenv('REDIS_HOST', '127.0.0.1'),
        'port': os.getenv('REDIS_PORT', 6379),
        'password': os.getenv('REDIS_PWD', '123456')
    }
redis_uri = 'redis://:{password}@{host}:{port}/0'.format(**redis_config)
redis = Redis.from_url(redis_uri)