Ubuntu Server Guide Documentation Linux 20.04 LTS (Focal Fossa)

Support documentation for Ubuntu 20.04 (Open Source / Red Hat) Installation Guide Ubuntu Server Guide Improving the Documentation PDFs and Previous Releases Support Basic installation Preparing to Install System requirements Server and Desktop Differences Backing Up Preparing install media Booting the installer Using the installer Advanced Installation Software RAID RAID Configuration Partitioning Degraded RAID RAID Maintenance Resources Logical Volume Manager (LVM) Overview Installation Extending Volume Groups Resources iSCSI Installation on a diskless system Installation on a system with disk attached Installation with iBFT Rebooting to an iSCSI target Package Management Introduction Apt Aptitude Command Line Aptitude dpkg APT Configuration Extra Repositories Automatic Updates Notifications References Kernel Crash Dump Introduction Kernel Crash Dump Mechanism Installation Configuration Local Kernel Crash Dumps Remote Kernel Crash Dumps using the SSH protocol Remote Kernel Crash Dumps using the NFS protocol Verification Testing the Crash Dump Mechanism Resources Reporting Bugs in Ubuntu Server Reporting Bugs With apport-cli Reporting Application Crashes Resources Upgrading do-release-upgrade Device Mapper Multipathing - Introduction Overview Storage Array Overview Multipath Components Multipath Setup Overview Multipath Devices Multipath Device Identifiers Consistent Multipath Device Names in a Cluster Multipath Device attributes Multipath Devices in Logical Volumes Device Mapper Multipathing - Configuration Configuration File Overview Configuration File Defaults Configuration File Blacklist & Exceptions Configuration File Multipath Section Configuration File Devices Section Device Mapper Multipathing - Setup Basic Setup Device Mapper Multipathing - Usage & Debug Resizing Online Multipath Devices Moving root File System from a Single Path Device to a Multipath Device The Multipath Daemon Multipath Command Output Multipath Queries with multipath Command Determining Device Mapper Entries with dmsetup Command Troubleshooting with the multipathd interactive console Networking TCP/IP TCP/IP Introduction TCP/IP Configuration IP Routing TCP and UDP ICMP Daemons Resources Network Configuration Ethernet Interfaces Identify Ethernet Interfaces Ethernet Interface Logical Names Ethernet Interface Settings IP Addressing Temporary IP Address Assignment Dynamic IP Address Assignment (DHCP Client) Static IP Address Assignment Loopback Interface Name Resolution Static Hostnames Name Service Switch Configuration Bridging networkd-dispatcher for pre-up, post-up, etc. hook scripts Resources Dynamic Host Configuration Protocol (DHCP) Installation Configuration References Time Synchronization Synchronizing your systems time Configuring timedatectl and timesyncd Serve the Network Time Protocol chrony(d) Installation Chronyd Configuration Serving the NTP Protocol View status PPS Support Example configuration for GPSD to feed Chrony References Data Plane Development Kit Prerequisites Unassigning the default Kernel drivers Usage: DPDK Device configuration DPDK HugePage configuration Compile DPDK Applications DPDK in KVM Guests Use DPDK Resources OpenVswitch-DPDK Attaching DPDK ports to OpenVswitch OpenVswitch DPDK to KVM Guests Tuning Openvswitch-DPDK Support and Troubleshooting Resources Security User Management Where is root? Adding and Deleting Users User Profile Security Password Policy Minimum Password Length Password Expiration Other Security Considerations SSH Access by Disabled Users External User Database Authentication AppArmor Using AppArmor Profiles Creating a Profile Updating Profiles Further pre-existing Profiles Checking and debugging denies Profile customization References Firewall Introduction ufw - Uncomplicated Firewall ufw Application Integration IP Masquerading ufw Masquerading iptables Masquerading Logs Other Tools References Certificates Types of Certificates Generating a Certificate Signing Request (CSR) Creating a Self-Signed Certificate Installing the Certificate Certification Authority References Console Security Disable Ctrl+Alt+Delete eCryptfs is deprecated Usage Find available images Launch a fresh instance of the current Ubuntu LTS Check out the running instances Learn more about the VM instance you just launched Connect to a running instance Run commands inside an instance from outside Stop an instance to save resources Delete the instance Integrate into the rest of your virtualization Get help Qemu Running Qemu/KVM Graphics Upgrading the machine type QEMU usage for microvms libvirt Virtual Networking Installation Virtual Machine Management virsh system and session scope Migration Device Passthrough / Hotplug Access Qemu Monitor via libvirt Huge Pages Huge page allocation Huge page usage in libvirt Apparmor isolation Resources Cloud images and uvtool Introduction Creating virtual machines using uvtool Uvtool packages Get the Ubuntu Cloud Image with uvt-simplestreams-libvirt Create the VM using uvt-kvm Connect to the running VM Get the list of running VMs Destroy your VM More uvt-kvm options Resources Introduction Virtual Machine Manager virt-manager guest lifecycle virt-manager guest modification Virtual Machine Viewer virt-install virt-clone Resources LXD Online Resources Installation Kernel preparation Configuration Creating your first container Creating a container LXD Server Configuration Authentication Backing store Container configuration Profiles Nesting Limits UID mappings and Privileged containers Apparmor Seccomp Raw LXC configuration Snapshots Publishing images Image export and import Troubleshooting LXC Installation Basic usage Basic privileged usage User namespaces Basic unprivileged usage Nesting Global configuration Networking LXC startup Backing Stores Templates Autostart Apparmor Customizing container policies Control Groups Cloning Snapshots Ephemeral Containers Lifecycle management hooks Consoles Troubleshooting Logging Monitoring container status Attach Container init verbosity LXC API Security Exploitable system calls Resources Databases MySQL Installation Configuration Database Engines Advanced configuration Creating a tuned configuration MySQL Tuner Resources PostgreSQL Installation Configuration Streaming Replication Backups Resources Active Directory Integration Accessing a Samba Share Accessing a Windows Share Resources As a Domain Controller Primary Domain Controller Backup Domain Controller Resources File Server Installation Configuration Resources Samba Introduction Print Server Installation Configuration Resources Securing File and Print Server Samba Security Modes Security = User Share Security Groups File Permissions Samba AppArmor Profile Resources Samba - OpenLDAP Backend Software Installation LDAP Configuration Samba schema Samba indices Adding Samba LDAP objects Samba Configuration Resources CUPS - Print Server Installation Configuration Web Interface References Domain Name Service (DNS) Installation Configuration Overview Caching Nameserver Forward Zone File Reverse Zone File Secondary Server Troubleshooting Testing resolv.conf ping named-checkzone Quick temporary query logging Logging References FTP Server vsftpd - FTP Server Installation Anonymous FTP Configuration User Authenticated FTP Configuration Securing FTP References iSCSI Initiator (or Client) Network Interfaces Configuration iSCSI Initiator Install iSCSI Initiator Configuration iSCSI Network Configuration Accessing the Logical Units (or LUNs) References Kerberos Overview Kerberos Server Installation Configuration Secondary KDC Kerberos Linux Client Installation Configuration Resources Kerberos and LDAP Configuring OpenLDAP Primary KDC Configuration (LDAP) Secondary KDC Configuration (LDAP) Resources OpenLDAP Server Post-install Inspection Modifying/Populating your Database Adding an index Change the rootDN password: Adding a schema Logging Backup and Restore References OpenLDAP Replication Provider Configuration - replication user Provider Configuration - standard replication Consumer Configuration - standard replication Provider Configuration - delta replication Add syncprov and accesslog overlays and DBs Consumer Configuration Testing References LDAP Workstation Authentication User and Group Management - ldapscripts Resources LDAP & TLS Network File System (NFS) Installation Configuration NFS Client Configuration References OpenSSH Server Introduction Installation Configuration SSH Keys Import keys from public keyservers Two factor authentication with U2F/FIDO References VPN OpenVPN Server Installation Public Key Infrastructure Setup Certificate Authority Setup Server Keys and Certificates Client Certificates Simple Server Configuration Simple Client Configuration First trouble shooting Advanced configuration Advanced routed VPN configuration on server Advanced bridged VPN configuration on server References Installing a gitolite server Gitolite configuration Managing gitolite users and repositories Using your server References Client software implementations Linux Network-Manager GUI for OpenVPN OpenVPN with GUI for Mac OS X OpenVPN with GUI for Win References SSSD SSSD and Active Directory Prerequisites, Assumptions, and Requirements Software Installation Join the domain SSSD Configuration Automatic home directory creation Checks Kerberos Tickets Desktop Ubuntu Authentication Resources SSSD and LDAP Prerequisites, Assumptions, and Requirements Software Installation SSSD Configuration Automatic home directory creation Check SSL setup on the client Final verification SSSD, LDAP and Kerberos Prerequisites, Assumptions, and Requirements Software Installation SSSD Configuration Automatic home directory creation Final verification SSSD and KDC spoofing Debugging and troubleshooting debug_level Caching Dovecot Server Installation Configuration Dovecot SSL Configuration Firewall Configuration for an Email Server References Exim4 Installation Configuration SMTP Authentication Configuring SASL References Email Services Postfix Installation Basic Configuration SMTP Authentication Configuring SASL Testing Troubleshooting Escaping chroot SMTPS Log Viewing Increasing Logging Detail Logging mail delivery Increasing daemon verbosity Logging SASL debug info Squid Installation Configuration References HTTPD - Apache2 Web Server Installation Configuration Basic Settings Default Settings apache2 Settings Apache2 Modules HTTPS Configuration Sharing Write Permission References Web Servers Implementation Introduction to High Availability High Availability Clusters High Availability Cluster Heartbeat High Availability Cluster Quorum Example Fencing Linux High Availability Projects Ubuntu HA Core Packages Ubuntu HA Community Packages Ubuntu HA Deprecated Packages Ubuntu HA Related Packages Upstream Documentation Ubuntu HA - Pacemaker Resource Agents Supportability Resource Agents: [main] Resource Agents: [universe] Resource Agents: [universe]-community Resource Agents: [non-supported] Resource Agents: [deprecated] Ubuntu HA - Pacemaker Fence Agents Supportability Fence Agents: [main] Fence Agents: [universe] Fence Agents: [universe]-community Fence Agents: [non-supported] Fence Agents: [deprecated] Ubuntu HA - DRBD Configuration Testing References Byobu Resources etckeeper Resources Munin Installation Configuration Additional Plugins References Nagios Installation Configuration Overview Configuration References pam_motd Resources Puppet Preconfiguration Installation Configuration Resources Monitoring Overview Nagios Installation Configuration Overview Configuration References Munin Installation Configuration Additional Plugins References Rsnapshot Configuration Test Configuration Scheduling Backups References PHP - Scripting Language Installation Configuration Testing References Ruby on Rails Installation Configuration Web Server Database References Backups Archive Rotation Rotating NFS Archives Tape Drives Bacula Overview Installation Configuration Localhost Backup Resources Shell Scripts Simple Shell Script Executing the Script Executing from a Terminal Executing with cron Restoring from the Archive References LAMP Applications Overview phpMyAdmin Installation Configuration References WordPress Installation Configuration References Using the installer Getting the installer Installer UI generalities Running the installer over serial Help menu Switching to a shell prompt Global keys Using the installer step by step Language selection Refresh Keyboard Zdev (s390x only) Network Proxy Mirror Storage Identity SSH Snaps Installation logs Configuring storage in the server installer Guided options The main storage screen Partitions RAID LVM Selecting boot devices Limitations and workarounds Automated Server Installs Introduction Differences from debian-installer preseeding Providing the autoinstall config Running a truly automatic autoinstall Quick start Creating an autoinstall config The structure of an autoinstall config Error handling Possible future directions Autoinstall Quick Start Providing the autoinstall data over the network Download the ISO Mount the ISO Write your autoinstall config Serve the cloud-init config over http Create a target disk Run the install! Boot the installed system Using another volume to provide the autoinstall config Download the live-server ISO Create your user-data & meta-data files Create an ISO to use as a cloud-init data source Create a target disk Run the install! Boot the installed system JSON Schema for autoinstall config Introduction How the config is validated Schema Regeneration Automated Server Installs Config File Reference Overall format Schema Top-level keys update channel layout variant toggle Supported layouts action-based config realname username hostname password install-server authorized-keys allow-pw Netbooting the server installer on amd64 Configuring DHCP/bootp and tftp Serving the bootloaders and configuration. Mode independent set up Setting up the files for UEFI booting Setting up the files for legacy boot Netbooting the Live Server Installer via UEFI PXE on Arm (aarch64, arm64) and x86_64 (amd64) Configuring TFTP Serving Files Necessary Files Examples Download and Serve Grub EFI Binary Download and Serve More Files Appendix Always Make Sure of the Serving File Names Booting Screenshots Eventually the initial subiquity installer screen shows up: Cloud Images Public Clouds Compute Offerings Container Offerings Private Clouds Release Support Amazon EC2 Images Find Images with SSM Image Locator AWS EKS AWS Marketplace Google Cloud Engine Images Finding Images Image Locator