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張 旭

Manage swarm security with public key infrastructure (PKI) | Docker Documentation - 0 views

  • The nodes in a swarm use mutual Transport Layer Security (TLS) to authenticate, authorize, and encrypt the communications with other nodes in the swarm.
  • By default, the manager node generates a new root Certificate Authority (CA) along with a key pair, which are used to secure communications with other nodes that join the swarm.
  • The manager node also generates two tokens to use when you join additional nodes to the swarm: one worker token and one manager token.
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  • Each time a new node joins the swarm, the manager issues a certificate to the node
  • By default, each node in the swarm renews its certificate every three months.
  • a cluster CA key or a manager node is compromised, you can rotate the swarm root CA so that none of the nodes trust certificates signed by the old root CA anymore.
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    "The nodes in a swarm use mutual Transport Layer Security (TLS) to authenticate, authorize, and encrypt the communications with other nodes in the swarm."
張 旭

How services work | Docker Documentation - 0 views

  • a service is the image for a microservice within the context of some larger application.
  • When you create a service, you specify which container image to use and which commands to execute inside running containers.
  • an overlay network for the service to connect to other services in the swarm
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  • In the swarm mode model, each task invokes exactly one container
  • A task is analogous to a “slot” where the scheduler places a container.
  • A task is the atomic unit of scheduling within a swarm.
  • A task is a one-directional mechanism. It progresses monotonically through a series of states: assigned, prepared, running, etc.
  • Docker swarm mode is a general purpose scheduler and orchestrator.
  • Hypothetically, you could implement other types of tasks such as virtual machine tasks or non-containerized process tasks.
  • If all nodes are paused or drained, and you create a service, it is pending until a node becomes available.
  • reserve a specific amount of memory for a service.
  • impose placement constraints on the service
  • As the administrator of a swarm, you declare the desired state of your swarm, and the manager works with the nodes in the swarm to create that state.
  • two types of service deployments, replicated and global.
  • A global service is a service that runs one task on every node.
  • Good candidates for global services are monitoring agents, an anti-virus scanners or other types of containers that you want to run on every node in the swarm.
張 旭

Swarm Mode Cluster - Træfik - 0 views

  • The only requirement for Træfik to work with swarm mode is that it needs to run on a manager node
  •  
    "The only requirement for Træfik to work with swarm mode is that it needs to run on a manager node"
張 旭

Deploy a registry server | Docker Documentation - 0 views

  • By default, secrets are mounted into a service at /run/secrets/<secret-name>
  • docker secret create
  • If you use a distributed storage driver, such as Amazon S3, you can use a fully replicated service. Each worker can write to the storage back-end without causing write conflicts.
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  • You can access the service on port 443 of any swarm node. Docker sends the requests to the node which is running the service.
  • --publish published=443,target=443
  • The most important aspect is that a load balanced cluster of registries must share the same resources
  • S3 or Azure, they should be accessing the same resource and share an identical configuration.
  • you must make sure you are properly sending the X-Forwarded-Proto, X-Forwarded-For, and Host headers to their “client-side” values. Failure to do so usually makes the registry issue redirects to internal hostnames or downgrading from https to http.
  • A properly secured registry should return 401 when the “/v2/” endpoint is hit without credentials
  • registries should always implement access restrictions.
  • REGISTRY_AUTH=htpasswd
  • REGISTRY_AUTH_HTPASSWD_PATH=/auth/htpasswd
  • The registry also supports delegated authentication which redirects users to a specific trusted token server. This approach is more complicated to set up, and only makes sense if you need to fully configure ACLs and need more control over the registry’s integration into your global authorization and authentication systems.
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    "You can access the service on port 443 of any swarm node. Docker sends the requests to the node which is running the service. "
張 旭

Variables - Ansible Documentation - 0 views

  • with the last listed variables winning prioritization
  • anything that goes into “role defaults” (the defaults folder inside the role) is the most malleable and easily overridden.
  • Anything in the vars directory of the role overrides previous versions of that variable in namespace.
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  • with command line -e extra vars always winning
張 旭

Basics - Træfik - 0 views

  • Modifier rules only modify the request. They do not have any impact on routing decisions being made.
  • A frontend consists of a set of rules that determine how incoming requests are forwarded from an entrypoint to a backend.
  • Entrypoints are the network entry points into Træfik
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  • Modifiers and matchers
  • Matcher rules determine if a particular request should be forwarded to a backend
  • if any rule matches
  • if all rules match
  • In order to use regular expressions with Host and Path matchers, you must declare an arbitrarily named variable followed by the colon-separated regular expression, all enclosed in curly braces.
  • Use a *Prefix* matcher if your backend listens on a particular base path but also serves requests on sub-paths. For instance, PathPrefix: /products would match /products but also /products/shoes and /products/shirts. Since the path is forwarded as-is, your backend is expected to listen on /products
  • Use Path if your backend listens on the exact path only. For instance, Path: /products would match /products but not /products/shoes.
  • Modifier rules ALWAYS apply after the Matcher rules.
  • A backend is responsible to load-balance the traffic coming from one or more frontends to a set of http servers
  • wrr: Weighted Round Robin
  • drr: Dynamic Round Robin: increases weights on servers that perform better than others.
  • A circuit breaker can also be applied to a backend, preventing high loads on failing servers.
  • To proactively prevent backends from being overwhelmed with high load, a maximum connection limit can also be applied to each backend.
  • Sticky sessions are supported with both load balancers.
  • When sticky sessions are enabled, a cookie is set on the initial request.
  • The check is defined by a path appended to the backend URL and an interval (given in a format understood by time.ParseDuration) specifying how often the health check should be executed (the default being 30 seconds). Each backend must respond to the health check within 5 seconds.
  • The static configuration is the global configuration which is setting up connections to configuration backends and entrypoints.
  • We only need to enable watch option to make Træfik watch configuration backend changes and generate its configuration automatically.
  • Separate the regular expression and the replacement by a space.
  • a comma-separated key/value pair where both key and value must be literals.
  • namespacing of your backends happens on the basis of hosts in addition to paths
  • Modifiers will be applied in a pre-determined order regardless of their order in the rule configuration section.
  • customize priority
  • Custom headers can be configured through the frontends, to add headers to either requests or responses that match the frontend's rules.
  • Security related headers (HSTS headers, SSL redirection, Browser XSS filter, etc) can be added and configured per frontend in a similar manner to the custom headers above.
  • Servers are simply defined using a url. You can also apply a custom weight to each server (this will be used by load-balancing).
  • Maximum connections can be configured by specifying an integer value for maxconn.amount and maxconn.extractorfunc which is a strategy used to determine how to categorize requests in order to evaluate the maximum connections.
張 旭

10 Common Git Problems and How to Fix Them - DEV Community - 0 views

  • Please keep in mind that --amend actually will create a new commit which replaces the previous one, so don’t use it for modifying commits which already have been pushed to a central repository.
  • git rebase --interactive
  • Just pick the commit(s) you want to update, change pick to reword (or r for short), and you will be taken to a new view where you can edit the message.
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  • you can completely remove commits by deleting them from the list, as well as edit, reorder, and squash them.
  • Squashing allows you to merge several commits into one
  • In case you don’t want to create additional revert commits but only apply the necessary changes to your working tree, you can use the --no-commit/-n option.
  • reuse recorded resolution
  • Unfortunately it turns out that one of the branches isn’t quite there yet, so you decide to un-merge it again. Several days (or weeks) later when the branch is finally ready you merge it again, but thanks to the recorded resolutions, you won’t have to resolve the same merge conflicts again.
  • You can also define global hooks to use in all your projects by creating a template directory that git will use when initializing a new repository
  • removing sensitive data
  • Keep in mind that this will rewrite your project’s entire history, which can be very disruptive in a distributed workflow.
crazylion lee

Pandoc - About pandoc - 0 views

shared by crazylion lee on 31 Aug 18 - No Cached
crazylion lee

Træfik - 0 views

shared by crazylion lee on 31 Aug 18 - No Cached
張 旭

What Is a Service Mesh? - NGINX - 0 views

  • The mesh provides service discovery, load balancing, encryption, authentication and authorization, support for the circuit breaker pattern, and other capabilities.
  • The service mesh is usually implemented by providing a proxy instance, called a sidecar, for each service instance
  • the term service is often used for both the instance definitions and the instances themselves.
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  • A sidecar proxy is a proxy instance that’s dedicated to a specific service instance.
  • The container management framework keeps a list of instances that are ready to receive requests.
  • The service mesh can encrypt and decrypt requests and responses
  • a service mesh application also includes a monitoring and management layer, called the control plane.
  • Service mesh architectures are not ever likely to be the answer to all application development and delivery problems
張 旭

Use swarm mode routing mesh | Docker Documentation - 0 views

  • Docker Engine swarm mode makes it easy to publish ports for services to make them available to resources outside the swarm.
  • All nodes participate in an ingress routing mesh.
  • routing mesh enables each node in the swarm to accept connections on published ports for any service running in the swarm, even if there’s no task running on the node.
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  • Port 7946 TCP/UDP for container network discovery
  • Port 4789 UDP for the container ingress network.
  • When you access port 8080 on any node, the swarm load balancer routes your request to an active container.
  • The routing mesh listens on the published port for any IP address assigned to the node.
  • publish a port for an existing service
  • To use an external load balancer without the routing mesh, set --endpoint-mode to dnsrr instead of the default value of vip
張 旭

NAT Gateways - Amazon Virtual Private Cloud - 0 views

  • a network address translation (NAT) gateway to enable instances in a private subnet to connect to the internet or other AWS services
  • but prevent the internet from initiating a connection with those instances
  • NAT gateways are not supported for IPv6 traffic
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  • must specify the public subnet in which the NAT gateway should reside
  • update the route table associated with one or more of your private subnets to point Internet-bound traffic to the NAT gateway.
  • NAT gateway is created in a specific Availability Zone and implemented with redundancy in that zone.
  • ensure that resources use the NAT gateway in the same Availability Zone
  • The main route table sends internet traffic from the instances in the private subnet to the NAT gateway. The NAT gateway sends the traffic to the internet gateway using the NAT gateway’s Elastic IP address as the source IP address
  • A NAT gateway supports 5 Gbps of bandwidth and automatically scales up to 45 Gbps
  • You can associate exactly one Elastic IP address with a NAT gateway
  • A NAT gateway supports the following protocols: TCP, UDP, and ICMP
  • cannot associate a security group with a NAT gateway.
  • create a NAT gateway in the same subnet as your NAT instance, and then replace the existing route in your route table that points to the NAT instance with a route that points to the NAT gateway
  • A NAT gateway cannot send traffic over VPC endpoints, VPN connections, AWS Direct Connect, or VPC peering connections.
張 旭

VPCs and Subnets - Amazon Virtual Private Cloud - 0 views

  • you must specify a range of IPv4 addresses for the VPC in the form of a Classless Inter-Domain Routing (CIDR) block
  • A VPC spans all the Availability Zones in the region
  • add one or more subnets in each Availability Zone.
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  • Each subnet must reside entirely within one Availability Zone and cannot span zones.
  • Availability Zones are distinct locations that are engineered to be isolated from failures in other Availability Zones
  • If a subnet's traffic is routed to an internet gateway, the subnet is known as a public subnet.
  • If a subnet doesn't have a route to the internet gateway, the subnet is known as a private subnet.
  • If a subnet doesn't have a route to the internet gateway, but has its traffic routed to a virtual private gateway for a VPN connection, the subnet is known as a VPN-only subnet.
  • By default, all VPCs and subnets must have IPv4 CIDR blocks—you can't change this behavior.
  • The allowed block size is between a /16 netmask (65,536 IP addresses) and /28 netmask (16 IP addresses).
  • The first four IP addresses and the last IP address in each subnet CIDR block are not available for you to use
  • The allowed block size is between a /28 netmask and /16 netmask
  • The CIDR block must not overlap with any existing CIDR block that's associated with the VPC.
  • Each subnet must be associated with a route table
  • Every subnet that you create is automatically associated with the main route table for the VPC
  • Security groups control inbound and outbound traffic for your instances
  • network ACLs control inbound and outbound traffic for your subnets
  • each subnet must be associated with a network ACL
  • You can create a flow log on your VPC or subnet to capture the traffic that flows to and from the network interfaces in your VPC or subnet.
  • A VPC peering connection enables you to route traffic between the VPCs using private IP addresses
  • you cannot create a VPC peering connection between VPCs that have overlapping CIDR blocks
  • recommend that you create a VPC with a CIDR range large enough for expected future growth, but not one that overlaps with current or expected future subnets anywhere in your corporate or home network, or that overlaps with current or future VPCs
張 旭

What Is Amazon VPC? - Amazon Virtual Private Cloud - 0 views

  • to allow an instance in your VPC to initiate outbound connections to the internet but prevent unsolicited inbound connections from the internet, you can use a network address translation (NAT) device for IPv4 traffic
  • A NAT device has an Elastic IP address and is connected to the internet through an internet gateway.
  • By default, each instance that you launch into a nondefault subnet has a private IPv4 address, but no public IPv4 address, unless you specifically assign one at launch, or you modify the subnet's public IP address attribute.
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  • Amazon VPC is the networking layer for Amazon EC2.
  • A virtual private cloud (VPC) is a virtual network dedicated to your AWS account. It is logically isolated from other virtual networks in the AWS Cloud.
  • Instances can connect to the internet over IPv6 through an internet gateway
  • IPv6 traffic is separate from IPv4 traffic; your route tables must include separate routes for IPv6 traffic.
  • You can optionally connect your VPC to your own corporate data center using an IPsec AWS managed VPN connection, making the AWS Cloud an extension of your data center.
  • A VPN connection consists of a virtual private gateway attached to your VPC and a customer gateway located in your data center.
  • A virtual private gateway is the VPN concentrator on the Amazon side of the VPN connection. A customer gateway is a physical device or software appliance on your side of the VPN connection.
  • AWS PrivateLink is a highly available, scalable technology that enables you to privately connect your VPC to supported AWS services, services hosted by other AWS accounts (VPC endpoint services)
  • Traffic between your VPC and the service does not leave the Amazon network
  • To use AWS PrivateLink, create an interface VPC endpoint for a service in your VPC. This creates an elastic network interface in your subnet with a private IP address that serves as an entry point for traffic destined to the service.
  • create your own AWS PrivateLink-powered service (endpoint service) and enable other AWS customers to access your service.
張 旭

Internet Gateways - Amazon Virtual Private Cloud - 0 views

  • to provide a target in your VPC route tables for internet-routable traffic
  • to perform network address translation (NAT) for instances that have been assigned public IPv4 addresses
  • Ensure that instances in your subnet have a globally unique IP address (public IPv4 address, Elastic IP address, or IPv6 address)
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  • To use an internet gateway, your subnet's route table must contain a route that directs internet-bound traffic to the internet gateway.
  • If your subnet is associated with a route table that has a route to an internet gateway, it's known as a public subnet.
  • To enable communication over the internet for IPv4, your instance must have a public IPv4 address or an Elastic IP address that's associated with a private IPv4 address on your instance.
  • Your instance is only aware of the private (internal) IP address space defined within the VPC and subnet
  • internet gateway logically provides the one-to-one NAT on behalf of your instance
  • To enable communication over the internet for IPv6, your VPC and subnet must have an associated IPv6 CIDR block, and your instance must be assigned an IPv6 address from the range of the subnet.
  • When you create a subnet, we automatically associate it with the main route table for the VPC.
  • the main route table doesn't contain a route to an internet gateway
  • Each instance that you launch into a VPC is automatically associated with its default security group.
  • a default security group allow no inbound traffic from the internet and allow all outbound traffic to the internet.
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