Posts

A python script that allows your terminal to snow.

A python script that allows your terminal to snow. docker run --rm -ti sontek/snowmachine tree --color rainbow --particle "*" --snow true --lights-color rainbow

Sunday, December 24, 2023 閱讀

Add SFTP user and share directory

Add SFTP user and share directory dev_test_user, qa_test_user 同權限 dev_user, qa_user 同權限 1. 建立共享資料夾(SFTP 使用的資料夾) sudo mkdir -p /home/{test,prod}/{exchange,upload} sudo mkdir -p /home/{test,prod}/exchange/success sudo mkdir -p /home/{test,prod}/upload/backup 2. 建立使用者群組 sudo groupadd share01-test sudo groupadd share01-prod 3. 創建 qa_test_user 使用者並設定 qa_test_user 使用者的群組為 share01-test sudo useradd -m -G share01-test qa_test_user # 設定 dev_test_user 使用者的群組為 share01-test sudo usermod -G share01-test dev_test_user # 設定密碼 sudo passwd qa_test_user 4. 創建 qa_user 使用者並設定 qa_user 使用者的群組為 share01-prod sudo useradd -m -G share01-prod qa_user # 設定 dev_user 使用者的群組為 share01-prod sudo usermod -G share01-prod dev_user # 設定密碼 sudo passwd qa_user 5. 設定權限 # 設定 /home/test 資料夾(含下級資料夾)的使用者為 qa_test_user，群組為 share01-test sudo chown -R qa_test_user:share01-test test/ # 設定 /home/prod 資料夾(含下級資料夾)的使用者為 qa_user，群組為 share01-prod sudo chown -R qa_user:share01-prod prod/ # SFTP 登入資料夾權限要給 root sudo chown root:root /home/test sudo chown root:root /home/prod 6. 設定 /etc/ssh/sshd_config /etc/ssh/sshd_config

Thursday, November 30, 2023 閱讀

Use terminal and SSH to remote host

Use terminal and SSH to remote host 1. Modern Terminals Hyper iTerm2 Tabby Warp Wez’s Terminal WindTerm 2. Open terminal in macOS ⌘ + space open Spotlight search terminal.app press ↩ 3. SSH to remote host ensure the private key file path. enter the command in the terminal: ssh -i /path/to/private_key.pem ubuntu@ubuntu.host.com

Friday, November 24, 2023 閱讀

Fetch GraphQL schema information

curl \ -XPOST \ -H "Content-Type: application/json" \ -d '{"query":"{__schema { types { name enumValues { name } fields { name type {name kind enumValues { name } ofType { name kind ofType {name kind}}}}}}}"}' \ https://example.com/graphql

Wednesday, October 18, 2023 閱讀

Container security fundamentals

Wednesday, October 4, 2023 閱讀

調整系統使得 EMQX 可以支援 1M 連線

Tuning EMQX to Scale to One Million Concurrent Connection on Kubernetes Performance Tuning (Linux) 矽谷牛的耕田筆記 Linux Kernel Tuning node level, basically the non-namespaced sysctls # Sets the maximum number of file handles allowed by the kernel sysctl -w fs.file-max=2097152 # Sets the maximum number of open file descriptors that a process can have sysctl -w fs.nr_open=2097152 namespaced sysctls # Sets the maximum number of connections that can be queued for acceptance by the kernel. sysctl -w net.core.somaxconn=32768 # Sets the maximum number of SYN requests that can be queued by the kernel sysctl -w net.ipv4.tcp_max_syn_backlog=16384 # Setting the minimum, default and maximum size of TCP Buffer sysctl -w net.ipv4.tcp_rmem='1024 4096 16777216' sysctl -w net.ipv4.tcp_wmem='1024 4096 16777216' # Setting Parameters for TCP Connection Tracking sysctl -w net.netfilter.nf_conntrack_tcp_timeout_time_wait=30 # Controls the maximum number of entries in the TCP time-wait bucket table sysctl -w net.ipv4.tcp_max_tw_buckets=1048576 # Controls Timeout for FIN-WAIT-2 Sockets: sysctl -w net.ipv4.tcp_fin_timeout=15 There are some more namespaced sysctls that will improve the performance but because of an active issue we are not able to set them on the container level # Sets the size of the backlog queue for the network device sysctl -w net.core.netdev_max_backlog=16384 # Amount of memory that is allocated for storing incoming and outgoing data for a socket sysctl -w net.core.rmem_default=262144 sysctl -w net.core.wmem_default=262144 # Setting the maximum amount of memory for the socket buffers sysctl -w net.core.rmem_max=16777216 sysctl -w net.core.wmem_max=16777216 sysctl -w net.core.optmem_max=16777216 Erlang VM Tuning ## Erlang Process Limit node.process_limit = 2097152 ## Sets the maximum number of simultaneously existing ports for this system node.max_ports = 2097152 EMQX Broker Tuning # Other configuration… EMQX_LISTENER__TCP__EXTERNAL: "0.0.0.0:1883" EMQX_LISTENER__TCP__EXTERNAL__ACCEPTORS: 64 EMQX_LISTENER__TCP__EXTERNAL__MAX_CONNECTIONS: 1024000

Wednesday, September 27, 2023 閱讀

Install Chrome OS

老電腦別丟掉！安裝 Google 免費作業系統安裝教學（Chrome OS Flex /CloudReady）

Wednesday, September 27, 2023 閱讀

永齡基金會AI大師論壇:人工智慧如何形塑人類未來

https://www.youtube.com/watch?v=M3z6gI1AEns

Wednesday, September 27, 2023 閱讀

Golang tips

GO 编程模式：切片，接口，时间和性能 Go 语言是一个高性能的语言，但并不是说这样我们就不用关心性能了，我们还是需要关心的。下面是一个在编程方面和性能相关的提示。如果需要把数字转字符串，使用 strconv.Itoa() 会比 fmt.Sprintf() 要快一倍左右尽可能地避免把 String 转成[]Byte 。这个转换会导致性能下降。如果在 for-loop 里对某个 slice 使用 append()请先把 slice 的容量很扩充到位，这样可以避免内存重新分享以及系统自动按 2 的 N 次方幂进行扩展但又用不到，从而浪费内存。使用 StringBuffer 或是 StringBuild 来拼接字符串，会比使用 + 或 += 性能高三到四个数量级。尽可能的使用并发的 go routine，然后使用 sync.WaitGroup 来同步分片操作避免在热代码中进行内存分配，这样会导致 gc 很忙。尽可能的使用 sync.Pool 来重用对象。使用 lock-free 的操作，避免使用 mutex，尽可能使用 sync/Atomic 包。（关于无锁编程的相关话题，可参看《无锁队列实现》或《无锁 Hashmap 实现》）使用 I/O 缓冲，I/O 是个非常非常慢的操作，使用 bufio.NewWrite() 和 bufio.NewReader() 可以带来更高的性能。对于在 for-loop 里的固定的正则表达式，一定要使用 regexp.Compile() 编译正则表达式。性能会得升两个数量级。如果你需要更高性能的协议，你要考虑使用 protobuf 或 msgp 而不是 JSON，因为 JSON 的序列化和反序列化里使用了反射。

Tuesday, September 26, 2023 閱讀

datavizproject

https://datavizproject.com

Tuesday, September 26, 2023 閱讀

朋友旅行防止絕交檢查表

https://travel-questions.gnehs.net/

Tuesday, September 26, 2023 閱讀

Cloudflare Zero Trust

Connect private networks Configure Local Domain Fallback Configure Split Tunnels Traffic routing with WARP 1. Set up the client Create device enrollment rules Create device enrollment rules to determine which devices can enroll to Zero Trust organization. Set device enrollment permissions In Zero Trust, go to Settings > WARP Client > Device enrollment > Device enrollment permissions > Manage. Rules > Policies > Add a rule > Include > Selector > Emails ending in > Value > @ruru910.com. 2. Route private network IPs through WARP In Zero Trust, go to Settings > WARP Client > Device settings > Profile settings > Profile name > Default > Configure. Configure settings: Enabled: Captive portal detection, Mode switch, Allow device to leave organization, Allow updates. Service mode: Gateway with WARP. Local Domain Fallback > Manage > Domain > nas.ruru910.com. Split Tunnels: Exclude IPs and domains > Manage. Delete the IP range of nas.ruru910.com. 3. Filter network traffic with Gateway 1. Enable the Gateway proxy In Zero Trust, go to Settings > Network. Gateway Logging: Capture all. Firewall: Proxy(TCP, UDP, ICMP), WARP to WARP, AV inspection. 2. Create Zero Trust policies Go to Access > Applications > Add an application > Private Network > Application Type > Destination IP. For Value, enter the IP address for your application (for example, 10.128.0.7). Modify policy > identify > Selector > User Email > in > @ruru910.com.

Tuesday, September 26, 2023 閱讀