LVS overview, Project Overview

LVS overview, Project Overview
LVS principle Overview: lvs is an open-source software short for Linux virtual server. It is a virtual server cluster system, the lvs cluster uses the ip Server Load balancer technology and content-based request distribution technology. The client requests are evenly transferred to different backend servers, and the scheduler automatically shields server faults. The entire server cluster structure is transparent to users. The cluster adopts a three-tier structure: Server Load balancer scheduling layer, application service cluster layer, and shared storage layer. The lvs scheduling layer is generally composed of two master-slave lvs servers. It balances loads on real servers and checks the integrity of services on each Real Server. Common Server Load balancer cluster software: lvs, haproxy, nginx high-availability cluster common software: heartbeat, keepalived, corosync + pacemaker (RHCS) function: ipvsadm is responsible for data distribution (Server Load balancer) keepalived is responsible for lvs server error detection and Health CheckLvs Load Balancing Technology:1. VS/NAT (Network Address Translation) 2. VS/DR (direct routing method) 3. VS/TUN (IP tunneling method) commonly used VS/DR and VS/TUNLvs architecture:The server cluster system built using lvs has three parts: the frontend server Load Balancer layer-Load Balancer; the intermediate server group layer-server Array; and the underlying data sharing layer-shared storage. Load Balancer layer: the Load Balancer layer is located at the frontend of the cluster system. It consists of one or more parent-child balancers (Director server). The lvs module is installed on Director server, director is mainly used in a vro, which contains a route table for completing the lvs function. Through these route tables, user requests are sent to the Real server, at the same time, the Real server monitoring module Ldirectord (integrated in heartbeat) is also installed on the Director server. This module is used to detect the health status of each Real server service. Server Array layer: consists of a group of machines running application services, including web services, mail services, ftp services, and dns services. In practical applications, Director server can also be used as the Real server role. Shared Storage layer: Provides Shared Storage space and content-consistent Storage areas for all Real servers. Generally, NFS/CIFS network files can be used to share data, however, NFS does not have good performance in busy business systems. This means you can use cluster file systems, such as the RedHat GFS2 file system and the ocfs2 file system provided by oracle. We can use iscsi, DM multi-path storage, MFS distributed file storage, and DRBD. From the entire lvs structure, we can see that Director server is the core of the entire lvs, and linux system (kernel 2.6) lvs is supported without any settings.LVS installation and configurationFirst: Use the ipvsadm command line to configure the second: use the Red Hat piranha tool to configure through the ipvsadm command line: 1. yun install ipvsadm2, load ipvs rules, save Rule 3. Bind vipifconfig eth0: 0 192.168.0.200 netmask 255.255.255.0 up4, Real server setting,/etc/sysctl on Director server. conf kernel settings 5. Real server interfaces and routing rules ifconfig lo: 0 192.168.0.200 netmask 255.255.255.255 uproute add-host 192.168.0.200 dev lo: 06. Test Access to the vip ip address repeatedly refresh the webpage. If different webpages appear, the request is successful.1. web load balancing with Red Hat PiranhaStatement: You can configure lvs directly on the web interface without having to go through the above configurations. The two Server Load balancer scheduling servers (Master/Slave) are relatively simple) vip and two Real server piranha solutions are a set of Load Balancing solutions based on lvs. One active lvs Server Load balancer scheduler and one backup yum install piranha-y configuration file/etc/sysconfig/ha/lvs. cf sets the password, starts the service, and enters the web interface configuration. ip: 3636 configures the master lvs and backup lvs, configures adding lvs (vip information), configures realserver information, and starts the lvs service pluse. Copy lvs. cf to the corresponding directory and test the connection status of ipvsadm-ln in the same way as that of the primary lvs. // check The lvs connection status.2. Build an lvs high-availability cluster through heartbeatOne master heartbeat server and one backup heartbeat server and two Real sever yum install heartbeat-libs heartbeat-devel ldirectord Modify/etc/ha. d/ha. cf file loading kernel load watchdog # modprobe softdog in/etc/modprobe. d. Add watchdog. confoptions softdog nowayout = 0 resource file/etc/ha. d/haresources modify the authentication file/etc/ha. d/authkeys permission 600 Configure/etc/ha. d/ldirectord. after the cf master heartbeat server is configured, copy/etc/ha. authkeys, haresources, and ha under the d directory. f. ldirectord. cf to the backup heartbeat server. After the service is started, an eth0: 0 interface will be added to the Real server for interface and route # ifconfig eth0: 0 192.168.0.200 netmask route 255.255.255.255 up # route add-host 192.168.0.200 dev eth0: 0 and then test ipvsadm-Lnc to view detailed links3. Build an lvs high-availability cluster through keepalivedTwo server Load balancer scheduling servers (Master/Slave), VIP, two Real server Source code compilation and installation of keepalived. /configure -- prefix =/usr/local/keepalived
In terms of electronics, I asked DRC, LVS, and P & R if they could be different from the three concepts I have mentioned and their usage methods, especially P & R.

Two Detection Methods: DRC and LVS

DRC checks the Layout
LVS checks whether the layout and circuit are consistent
 
The abbreviation of chemical preparation is DMF, DCM, DEM, LVS, LVA, and LVD. What does this mean?

DMF (Basic Information) CAS No.: 68-12-2 (Chinese name: dimethyl DMF) English name: DMF alias: N-methyl methacrylate dimethyl amine content: 99.95% Molecular formula: c3108no molecular weight: 73.09 FLASH: 58 ℃ Package: 190/barrel quality indicator (Specification) :( Useage) moisture; 0.03 ACIDITY: 0.01 refractive index: 1.427-1.429 color: 10 Useage (DMF) is an excellent organic solvent and an important chemical raw material. DMF can be widely used as polyurethane, acrylic and polyvinyl chloride. solvent of polymers with strong molecular gravity. it is used in synthesis of sulfadiamine, Baicalin and vitamin B6. it is used in the synthesis of acetamiprid. DMF is used to extract butadiene and other components in petrochemical industry. Physical Properties (DMF) appearance: colorless transparent liquid; polar inert solvent. it can be mixed with water and most organic solvents, except halogen-dimethyl DMF. melting Point-61 °C boiling point 152.8 °C. relative density 0. 9445. flash point 58 °C. refractive Index 1.4269 self-burning point: Storage and Transportation (Storeage) of 445 °C is packed in alloy steel, chromium and aluminum bucket or galvanized iron bucket, with a net weight of GK. use graphite instead of grease to lubricate the parts that are moved in contact with this product. storage and Transportation of DMF in accordance with the provisions of inflammable chemicals. the following describes the fraction of methylene chloride: CH2Cl2. It is a non-combustible low boiling point solvent, often used to replace flammable petroleum ether, ether, and so on, and can be used as dental local anesthesia, refrigerant and fire extinguishing agent. Directory [hidden] 1. Physical and chemical constants of substances 2. Environmental impact 3. Site Emergency Monitoring Methods 4. Laboratory monitoring methods 5. Environmental Standards 6. Emergency Treatment Methods 7. Preparation method

Electronic structured Methylene Chloride [edit this section] 1. Physical and chemical constants of substances: National Standard No. 61552
CAS Serial No. 75-09-2
EINECS region number 200-838-9
Chinese name methylene chloride
English name: Dichloromethane; Methylenechloride; methyene dichloride
Alias: dicross, dichlorine
The appearance and properties of the molecular CH2Cl2 and H2CCl2 are colorless, transparent, and volatile liquids. Irritating odor similar to ether
Molecular Weight 84.94
Resolution: 1.326
Boiling Point: 39.8 ℃
Vapor Pressure 30.55kPa (10 ℃)
Melting Point-95.1 ℃
Viscosity (20 ℃) 0.43mPa · s.
Refractive Index nD (20 deg C) 1.4244.
Critical Temperature 237 ℃,
Critical Pressure 0795MPa.
Soluble in about 50 times of water, soluble in phenol, aldehyde, ketone, ice acetic acid, Triethyl phosphate, ethyl acetate, and cyclamine. Mixed Solution with ethanol, ether and N, N-N
After pyrolysis, hydrochloric acid and trace photogases are generated, which are heated with water for a long time to generate formaldehyde and HCl. For further chloride, chl3 and C4. Colorless and volatile liquid. Difficult to burn. Vapor and air form an explosive mixture, explosion limit: 6.2% ~ 15.0% (volume ). Methylene chloride is used with sodium hydroxide to generate formaldehyde. In the industry, methylene chloride is produced by the reaction of natural gas and chlorine gas and obtained by rectification. It is an excellent organic solvent. It is slightly more irritating to the skin and mucous membrane than chloroform. Pay attention to it when using high concentrations of methylene chloride.
Galvanized iron bucket for packaging, storage and transportation is packed in a closed manner, with a barrel of 250 kg. Both train trucks and automobiles can be transported. It should be stored in cold, dark, dry, and well ventilated places. Pay attention to moisture-proof.
Hazard mark 15 (Hazardous Products) is mainly used as solvent in the resin and Plastic Industries... remaining full text>