• Using ANSI ble to write playbook to automatically install CEPH cluster in Huawei cloud batch configuration management tool


    Ansible, playbook, huaweiyun, CEPH First, purchase the virtual machine needed to build the CEPH cluster on Huawei cloud:       Then purchase the storage disk required by CEPH     Mount the purchased disk to the virtual machine used to build CEPH Installing ansible on the springboard machine Check the ansible version and verify […]

  • [continuous integration] gitlab CI + docker for continuous integration


    Gitlab CI + docker for continuous integration I. Basic concepts of continuous integration (CI) Summary In the development of traditional software, the integration of code is usually done when everyone completes the work and the project is about to end, which often takes a lot of time and energy. Continuous integration is an approach that […]

  • Analysis of interview questions


    ACL (access control list) access control list It includes three aspects: I. scheme 1. IP: permission control from IP address granularity 2. Digest: the most commonly used permission ID, similar to Username: password, is used for permission configuration to distinguish different applications for permission control 3. World: the most open way to control permissions is […]

  • Oracle utility SQL


    Start with connect by prior recursive query usage Select * from table name AA start with aa.id = ‘xxx’ connect by prior aa.id = aa.parentId ORDER BY … start withClause: traversal start condition connect byClause: connection condition. The keyword prime, which is put together with parent node column parent, is to traverse in the direction […]

  • Searching the nth last node in a single chain table of commonly used IOS algorithms (illustration)


    To get the title, first understand the data structure of the linked list, as shown in the following figure:        General idea: use the array to traverse the whole single chain table, load each node into the array, and finally get the array. According to the index (array length – 1-N), you will get […]

  • Kubernetes garbage collector source code analysis of the garbage collector controller (2)


    Kubernetes version: 1.13.2 Continue to the previous section: kubernetes garbage collector garbage collector controller source code analysis (1) Main steps The source code of the garbage collector controller is mainly divided into the following parts: monitorsAs a producer, put changing resources intographChangesQueues; at the same timerestMapperRegularly check the resource types in the cluster and refresh […]

  • Oracle 11gr2 RAC stop and start


    Grid can be executed in any directory after setting environment variables. If root is not set, absolute path is required.export ORACLE_HOME=/u01/app/11.2.0/gridexport PATH=$ORACLE_HOME/bin:$PATH–/U01 / APP / 11.2.0/grid/bin/crsctl or srvctl View the status of the cluster[[email protected] ~]$ crs_stat -t -v[[email protected] ~]$ srvctl status database -d TESTDB[[email protected] ~]$ srvctl status diskgroup -g DATA -n testdb2,testdb1[[email protected] ~]$ srvctl status […]

  • Forest before tree: the core content of elasticsearch upgrade


    When learning elasticsearch, because of the problems of each version, I couldn’t make it clear, and I had a headache. The official also gave the update of each version. However, the English version has a lot of update information. Recently, I have read a lot of materials, but none of them have been sorted out […]

  • On DOM operation of JS core


    An important function of JS is to operate Dom and change page display. Catalog: 1. Basic concepts 2. Node type 3. Node relationship 4. Node operation   Basic concepts The full name of DOM is document object model, that is, document object model. It is an API for HTML and XML. It describes a hierarchical […]

  • Deployment of load balancer in k8s


    In kubernetes, the IP address of the service and pod can only be used inside the cluster network, and it is not visible for applications outside the cluster. In order to enable external applications to access the services in the cluster, the following schemes are provided in kubernetes: NodePort LoadBalancer Ingress This section mainly introduces […]

  • Linux related collections


    This article is an overview. Linux xshell6 connection Hadoop Start and Close   Linux xshell 6 connection related issues   First of all, virtual machines have to be networked (Baidu can be a specific tutorial) Then, query the native IP (xshell 6 connection key) ==> IP addr   Finally, connect xshell6   Then connect.   Hadoop […]

  • Graphical single list inversion


    This paper mainly presents the specific process of chain inversion deduction in the form of graphs, in order to help understand and keep the train of thought clear. There are two main ways to achieve it.Single List Inversion: (1) AdoptionloopThe list is traversed by three pointers and reversed one by one. (2) UserecursionThe method is […]